Maize (Zea mays L.) ranks third as a food crop after wheat and rice and is characterized not only as a cereal crop but also as a vegetable. Maize used as a vegetable is known as “baby corn”. Baby corn consists of unfertilized young ears harvested 2 or 3 days after silk emergence. The present study was implemented in 2009 at Western Kentucky University Agriculture Research and Education Center (36.93 N, 86.47 E) in Bowling Green, Kentucky. The purpose of the study was to compare the effect of different schemes of harvest on baby corn (BC) yield, grain maize (GM) yield, and estimated economic return. Experimental harvest treatments were 1) no BC harvest, only GM harvest, 2) first harvest as BC, final harvest as GM, 3) first and second harvests as BC, final harvest as GM, and 4) first, second, and third harvests as BC, final harvest as GM. Average estimated BC yields (Kg/ha) for Treatments 2, 3, and 4 were 1445.1, 2681.8, and 3437.5; GM yields (Kg/ha) for Treatments 1, 2, and 3 were 12522.2, 8226.5, and 1380.9; respectively. Since few grain kernels were found after three harvests for BC (Treatment 4), no usable GM yield was produced. BC and GM yields were used for evaluating the economic returns. Results indicated that the sequence of best economic returns would be obtained by harvesting BC three times (Treatment 4), first two harvests for BC and the final for GM (Treatment 3), first harvest for BC and subsequent for GM (Treatment 2), and only for GM harvest (Treatment 1). Although the pattern for only BC harvest was the most profitable system, the human labor requirement and critical timing of harvest limited its production. In states similar to Kentucky, BC could only be grown as an additional crop or to supplant a limited amount of traditional GM hectarage.

In this study the action of high hydrostatic pressure (HHP) on compression heating of liquid foods and pressure transmitting fluids, inactivation of Escherichia coli and Listeria innocua in different food media (milk and fruit juices), pulsed pressure and high pressure carbon dioxide treatments was investigated. The experimental results in this study allowed pointing out some important results: (i) The thermal effects of compression should be taken into account when HHP pasteurization processes are developed. Initial temperature of the food product and compression rate should carefully be selected in order to compensate the compression heating / (ii) The HHP inactivation kinetics need not follow traditional first-order kinetics, hence alternative inactivation models are ought to be found. Weibull model can be used for HHP inactivation kinetics of microorganisms / (iii) The pulsed pressure treatment could be an alternative to continuous HHP, but optimization should be done between the pulse holding time, the number of pulses and the pressure level to reach the desirable number of log-reduction of microorganisms (E. coli and L. innocua) compatible with an industrial application / (iv) The storage duration and storage temperature after HHP treatment should carefully be optimized to increase the safety of HHP treated fruit juices since the growth of injured microorganisms can be avoided during storage / (v) The high pressure carbon dioxide (HPCD) treatment in combination with pulsed pressure can be an efficient way to inactivate the microorganisms in skim milk and to reduce the maximum pressure level for the desired log-reduction.

The annual Sigmon Farm Tour was started in 1992 as an agricultural education program where students could experience being on a farm with the goal of increasing the agricultural literacy levels of the participants. Every year the entire 4th grade student population of Rockcastle County spends the day touring the farm and participating in experiential mini lessons given by the cooperating farm service and health agencies. The program has continued for 20+ years without an evaluation as to whether it is achieving its objectives. This evaluation will also exhibit the programs strengths and weakness so it can continue to improve. This study utilized the pretest, posttest and delayed posttest to ascertain the agricultural literacy level of the student before the fieldtrip, after participating in the field trip and again 90 days later.

This study investigated pressure-induced starch gelatinisation in water and milk suspensions. A rheological method, termed ‘pasting curves’, provided an objective and analytical means to determine the degree of pressure-induced starch gelatinisation. In addition, a polarised light microscope was used to observe birefringence of the starch granules and the degree of starch swelling was measured. The preliminary investigation into pressure-induced gelatinisation of six different starches showed that potato starch was the most pressure resistant and was not gelatinised after a pressure treatment of 600 MPa for 30 min at 20 °C. Waxy rice, waxy corn and tapioca starches showed complete gelatinisation after the same treatment while normal rice and normal corn starches were only partially gelatinised despite the disappearance of birefringence. Based on the preliminary study, two starches (normal and waxy rice starches) were selected for more detailed studies. The effects of treatment conditions (pressure, temperature and duration) on the gelatinisation were investigated with these selected starches. The degree of gelatinisation was dependent on the type of starch and the treatment conditions. The results also indicated that different combinations of the treatment conditions (e.g. high treatment pressure for a short time and low treatment pressure for a longer time) could result in the same degree of gelatinisation. Both starch types exhibited sigmoidal-shaped pressure-induced gelatinisation curves and there was a linear correlation between the degree of swelling and the apparent viscosity of the starch suspension. After treatments at =500 MPa for 30 min at 20 °C, both starches lost all birefringence although the apparent viscosity and the degree of swelling of normal rice starch did not increase to the same extent as observed in waxy rice starch. Pressure-induced gelatinisation of starch was retarded when starch was suspended in skim milk. This was attributed to the effect of soluble milk minerals and lactose present in the milk whereas milk proteins (casein and whey) did not affect the degree of gelatinisation at the levels present in 10% total solids skim milk. The presence of soluble milk and/or lactose may lead to less effective plasticising of starch chains by the suspension medium. Interactions between milk components and starch molecules may also play a role in retarding gelatinisation by reducing the mobility of starch chains. The functionality of starch in a dairy application was tested using acid milk gels as a model system. Skim milk with added starch (waxy rice or potato starch) was either pressure treated (500 MPa, 20°C, 30 min) or heat treated (80°C, 30 min) and subsequently acidified to form acid milk gels. The addition of waxy rice starch resulted in firmer acid milk gels, and increasing the amount of starch caused an increase in the firmness of both pressure-treated and heat-treated samples. However, pressure-treated samples with added potato starch did not show significant changes in the firmness whereas the heat-treated counterparts showed a marked increase in the firmness as the level of potato starch increased. The difference between the effects of the two different starches can be explained by the extent of starch gelatinisation in skim milk. Starch granules absorb water during gelatinisation whether induced by pressure or heat which effectively increases milk protein concentration in the aqueous phase to form a denser protein gel network on acidification. The firmness of acid milk gels can be increased by adjusting the pH at pressure or heat treatment to higher than the natural pH of milk. The effect of pH at pressure or heat treatment and addition of starch on the acid milk gel firmness was additive and independent of each other up to a starch addition level of 1%. This study provided an insight into pressure-induced gelatinisation of starch by showing gelatinisation properties of starches of different botanical origins and the effects of the treatment conditions (treatment pressure, treatment temperature and duration) on the degree of gelatinisation. Furthermore, the results from the pressure treatments of starch in dairy-based suspensions showed that pressure-induced gelatinisation was affected by other components in the system. These results demonstrate the importance of understanding the gelatinisation properties of starch in complicated food systems in which a number of other components are present. In terms of the application of starch in dairy systems, when starch was added to milk and gelatinised by pressure treatment, the acid milk gel produced by subsequent acidification was firmer than the acid milk gel made from skim milk alone.

Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.

Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.

This study investigated pressure-induced starch gelatinisation in water and milk suspensions. A rheological method, termed ‘pasting curves’, provided an objective and analytical means to determine the degree of pressure-induced starch gelatinisation. In addition, a polarised light microscope was used to observe birefringence of the starch granules and the degree of starch swelling was measured. The preliminary investigation into pressure-induced gelatinisation of six different starches showed that potato starch was the most pressure resistant and was not gelatinised after a pressure treatment of 600 MPa for 30 min at 20 °C. Waxy rice, waxy corn and tapioca starches showed complete gelatinisation after the same treatment while normal rice and normal corn starches were only partially gelatinised despite the disappearance of birefringence. Based on the preliminary study, two starches (normal and waxy rice starches) were selected for more detailed studies. The effects of treatment conditions (pressure, temperature and duration) on the gelatinisation were investigated with these selected starches. The degree of gelatinisation was dependent on the type of starch and the treatment conditions. The results also indicated that different combinations of the treatment conditions (e.g. high treatment pressure for a short time and low treatment pressure for a longer time) could result in the same degree of gelatinisation. Both starch types exhibited sigmoidal-shaped pressure-induced gelatinisation curves and there was a linear correlation between the degree of swelling and the apparent viscosity of the starch suspension. After treatments at =500 MPa for 30 min at 20 °C, both starches lost all birefringence although the apparent viscosity and the degree of swelling of normal rice starch did not increase to the same extent as observed in waxy rice starch. Pressure-induced gelatinisation of starch was retarded when starch was suspended in skim milk. This was attributed to the effect of soluble milk minerals and lactose present in the milk whereas milk proteins (casein and whey) did not affect the degree of gelatinisation at the levels present in 10% total solids skim milk. The presence of soluble milk and/or lactose may lead to less effective plasticising of starch chains by the suspension medium. Interactions between milk components and starch molecules may also play a role in retarding gelatinisation by reducing the mobility of starch chains. The functionality of starch in a dairy application was tested using acid milk gels as a model system. Skim milk with added starch (waxy rice or potato starch) was either pressure treated (500 MPa, 20°C, 30 min) or heat treated (80°C, 30 min) and subsequently acidified to form acid milk gels. The addition of waxy rice starch resulted in firmer acid milk gels, and increasing the amount of starch caused an increase in the firmness of both pressure-treated and heat-treated samples. However, pressure-treated samples with added potato starch did not show significant changes in the firmness whereas the heat-treated counterparts showed a marked increase in the firmness as the level of potato starch increased. The difference between the effects of the two different starches can be explained by the extent of starch gelatinisation in skim milk. Starch granules absorb water during gelatinisation whether induced by pressure or heat which effectively increases milk protein concentration in the aqueous phase to form a denser protein gel network on acidification. The firmness of acid milk gels can be increased by adjusting the pH at pressure or heat treatment to higher than the natural pH of milk. The effect of pH at pressure or heat treatment and addition of starch on the acid milk gel firmness was additive and independent of each other up to a starch addition level of 1%. This study provided an insight into pressure-induced gelatinisation of starch by showing gelatinisation properties of starches of different botanical origins and the effects of the treatment conditions (treatment pressure, treatment temperature and duration) on the degree of gelatinisation. Furthermore, the results from the pressure treatments of starch in dairy-based suspensions showed that pressure-induced gelatinisation was affected by other components in the system. These results demonstrate the importance of understanding the gelatinisation properties of starch in complicated food systems in which a number of other components are present. In terms of the application of starch in dairy systems, when starch was added to milk and gelatinised by pressure treatment, the acid milk gel produced by subsequent acidification was firmer than the acid milk gel made from skim milk alone.

Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.

This study investigated pressure-induced starch gelatinisation in water and milk suspensions. A rheological method, termed ‘pasting curves’, provided an objective and analytical means to determine the degree of pressure-induced starch gelatinisation. In addition, a polarised light microscope was used to observe birefringence of the starch granules and the degree of starch swelling was measured. The preliminary investigation into pressure-induced gelatinisation of six different starches showed that potato starch was the most pressure resistant and was not gelatinised after a pressure treatment of 600 MPa for 30 min at 20 °C. Waxy rice, waxy corn and tapioca starches showed complete gelatinisation after the same treatment while normal rice and normal corn starches were only partially gelatinised despite the disappearance of birefringence. Based on the preliminary study, two starches (normal and waxy rice starches) were selected for more detailed studies. The effects of treatment conditions (pressure, temperature and duration) on the gelatinisation were investigated with these selected starches. The degree of gelatinisation was dependent on the type of starch and the treatment conditions. The results also indicated that different combinations of the treatment conditions (e.g. high treatment pressure for a short time and low treatment pressure for a longer time) could result in the same degree of gelatinisation. Both starch types exhibited sigmoidal-shaped pressure-induced gelatinisation curves and there was a linear correlation between the degree of swelling and the apparent viscosity of the starch suspension. After treatments at =500 MPa for 30 min at 20 °C, both starches lost all birefringence although the apparent viscosity and the degree of swelling of normal rice starch did not increase to the same extent as observed in waxy rice starch. Pressure-induced gelatinisation of starch was retarded when starch was suspended in skim milk. This was attributed to the effect of soluble milk minerals and lactose present in the milk whereas milk proteins (casein and whey) did not affect the degree of gelatinisation at the levels present in 10% total solids skim milk. The presence of soluble milk and/or lactose may lead to less effective plasticising of starch chains by the suspension medium. Interactions between milk components and starch molecules may also play a role in retarding gelatinisation by reducing the mobility of starch chains. The functionality of starch in a dairy application was tested using acid milk gels as a model system. Skim milk with added starch (waxy rice or potato starch) was either pressure treated (500 MPa, 20°C, 30 min) or heat treated (80°C, 30 min) and subsequently acidified to form acid milk gels. The addition of waxy rice starch resulted in firmer acid milk gels, and increasing the amount of starch caused an increase in the firmness of both pressure-treated and heat-treated samples. However, pressure-treated samples with added potato starch did not show significant changes in the firmness whereas the heat-treated counterparts showed a marked increase in the firmness as the level of potato starch increased. The difference between the effects of the two different starches can be explained by the extent of starch gelatinisation in skim milk. Starch granules absorb water during gelatinisation whether induced by pressure or heat which effectively increases milk protein concentration in the aqueous phase to form a denser protein gel network on acidification. The firmness of acid milk gels can be increased by adjusting the pH at pressure or heat treatment to higher than the natural pH of milk. The effect of pH at pressure or heat treatment and addition of starch on the acid milk gel firmness was additive and independent of each other up to a starch addition level of 1%. This study provided an insight into pressure-induced gelatinisation of starch by showing gelatinisation properties of starches of different botanical origins and the effects of the treatment conditions (treatment pressure, treatment temperature and duration) on the degree of gelatinisation. Furthermore, the results from the pressure treatments of starch in dairy-based suspensions showed that pressure-induced gelatinisation was affected by other components in the system. These results demonstrate the importance of understanding the gelatinisation properties of starch in complicated food systems in which a number of other components are present. In terms of the application of starch in dairy systems, when starch was added to milk and gelatinised by pressure treatment, the acid milk gel produced by subsequent acidification was firmer than the acid milk gel made from skim milk alone.

Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.