This thesis relates the physicochemical properties of phenolic compounds to their antioxidant activities. It focuses on the partitioning of phenolic compounds between hydrophilic and lipophilic environments and the relevance this has to their in vivo health effects. Data in the literature was lacking so the phase partition coefficients (log P) of 53 phenolic antioxidants were measured by reversed-phase HPLC and calculated by log P prediction software. There was a very strong linear correlation between measured and calculated values (r=0.91). The importance of log P in determining antioxidant assay values was then tested by developing an assay system capable of measuring activities of both hydrophilic and lipophilic antioxidants. This Lipid Peroxidation Inhibition Capacity Assay (LPIC), based on using liposomes to simulate a cell membrane environment, was then used to measure the activity of antioxidants with a broad range of structures. The activities were correlated against log p, the difference of heat of formation (∆Hf) and half-wave potential (Ep/2) and used to derive a predictive model to calculate the LPIC activity. There was a highly significant linear correlation between the calculated and measured values. The LPIC activities also correlated well to published LDL inhibition activities but not to measured ORAC activities. These findings suggested that behaviours of antioxidants in the small unilamellar vesicles of the LPIC assay were similar to that in the LDL assay but not to the aqueous phase based ORAC assay. The LPIC assay may therefore be a better indicator of potential health benefits of antioxidants in the human body than the ORAC assay. The possible mechanistic reasons are that it may better reflect ability to prevent the oxidation of LDL blood stream particles that leads to cardiovascular disease and also takes into account the importance of membrane solubility which can raise the cellular concentration and thus potential to protect cells from oxidative damage. KEYWORDS: LPIC, LDL; Antioxidant; Phytochemical; Polyphenolic; Phenolic acid; Flavonoids; log P; Partition Coefficient; Liposome; Lipid bilayer; Lipid Membrane; ORAC; Comet assay; Flow Cytometry. / Whole document restricted, but available by request, use the feedback form to request access.

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Reducing oil content, minimizing any carcinogenic acrylamide in the high temperature frying process for potato crisps, and producing good products with considerable crispiness and acceptable color were the objectives of this research. Vacuum frying with pre-treatment of potato crisps was investigated as an effective process for oil content reduction. Pre-drying and subsequent dipping (PSSD) in a sugar solution (‘sugar dipping’) were considered as an advantageous procedure for the treatment of potato crisps before frying in order to reduce oil uptake during frying. Vacuum frying was observed as an excellent process to decrease significantly the acrylamide formation at low temperature frying of potato crisps. In this study, potato crisps were respectively blanched, pre-dried, and dipped in a solution of sugar (23.07 wt %) for two seconds, before vacuum frying at 120oC, 110oC under different vacuum pressures (170mbars, 150mbars, 100mbars and 50mbars in separate experiments). Conventional frying at 180oC was also used as the control to benchmark the reductions in the oil contents and acrylamide formation among various techniques. There was a significant reduction in oil content of the potato crisps observed when the new techniques were applied. The crisps that had been pre-treated and fried with conventional frying have given the result of 30 wt % reduction. The crisps that were fried under vacuum frying achieved greater oil reduction with varying percentages when applying different pretreatments. The lowest oil content was achieved when the potato crisps were fried at 110oC and 150 mbars giving 58 % reduction on the dry basis compared with control samples. There are various advantages of the technique with PSSD as we have discovered: it is simple and can be applied in potato crisp industries in continuous mode in both vacuum and conventional frying systems. The crisps that had been treated with pre-drying and subsequent sugar solution dipping and then fried were crunchier and possibly had better perceived taste to the consumer, due to the small sugar addition. Pre-drying and vacuum frying have all turned out to be excellent techniques to reduce acrylamide formation in potato crisps as we have found in this study. Vacuum frying at 120oC and 150 mbars reduced acrylamide formation by 80 to 85%. The 95% reduction was obtained when the crisps had been pre-dried. Acrylamide was undetectable when crisps were pre-dried and vacuum fried at 110oC, 150 mbars. The crisps with pre-drying subsequent sugar dipping and vacuum fried at low temperature had improved color compared with the control samples, which were produced by conventional frying at high temperatures. / Note: Part 3 publication restricted due to copyright restrictions.

Reducing oil content, minimizing any carcinogenic acrylamide in the high temperature frying process for potato crisps, and producing good products with considerable crispiness and acceptable color were the objectives of this research. Vacuum frying with pre-treatment of potato crisps was investigated as an effective process for oil content reduction. Pre-drying and subsequent dipping (PSSD) in a sugar solution (‘sugar dipping’) were considered as an advantageous procedure for the treatment of potato crisps before frying in order to reduce oil uptake during frying. Vacuum frying was observed as an excellent process to decrease significantly the acrylamide formation at low temperature frying of potato crisps. In this study, potato crisps were respectively blanched, pre-dried, and dipped in a solution of sugar (23.07 wt %) for two seconds, before vacuum frying at 120oC, 110oC under different vacuum pressures (170mbars, 150mbars, 100mbars and 50mbars in separate experiments). Conventional frying at 180oC was also used as the control to benchmark the reductions in the oil contents and acrylamide formation among various techniques. There was a significant reduction in oil content of the potato crisps observed when the new techniques were applied. The crisps that had been pre-treated and fried with conventional frying have given the result of 30 wt % reduction. The crisps that were fried under vacuum frying achieved greater oil reduction with varying percentages when applying different pretreatments. The lowest oil content was achieved when the potato crisps were fried at 110oC and 150 mbars giving 58 % reduction on the dry basis compared with control samples. There are various advantages of the technique with PSSD as we have discovered: it is simple and can be applied in potato crisp industries in continuous mode in both vacuum and conventional frying systems. The crisps that had been treated with pre-drying and subsequent sugar solution dipping and then fried were crunchier and possibly had better perceived taste to the consumer, due to the small sugar addition. Pre-drying and vacuum frying have all turned out to be excellent techniques to reduce acrylamide formation in potato crisps as we have found in this study. Vacuum frying at 120oC and 150 mbars reduced acrylamide formation by 80 to 85%. The 95% reduction was obtained when the crisps had been pre-dried. Acrylamide was undetectable when crisps were pre-dried and vacuum fried at 110oC, 150 mbars. The crisps with pre-drying subsequent sugar dipping and vacuum fried at low temperature had improved color compared with the control samples, which were produced by conventional frying at high temperatures. / Note: Part 3 publication restricted due to copyright restrictions.

Reducing oil content, minimizing any carcinogenic acrylamide in the high temperature frying process for potato crisps, and producing good products with considerable crispiness and acceptable color were the objectives of this research. Vacuum frying with pre-treatment of potato crisps was investigated as an effective process for oil content reduction. Pre-drying and subsequent dipping (PSSD) in a sugar solution (‘sugar dipping’) were considered as an advantageous procedure for the treatment of potato crisps before frying in order to reduce oil uptake during frying. Vacuum frying was observed as an excellent process to decrease significantly the acrylamide formation at low temperature frying of potato crisps. In this study, potato crisps were respectively blanched, pre-dried, and dipped in a solution of sugar (23.07 wt %) for two seconds, before vacuum frying at 120oC, 110oC under different vacuum pressures (170mbars, 150mbars, 100mbars and 50mbars in separate experiments). Conventional frying at 180oC was also used as the control to benchmark the reductions in the oil contents and acrylamide formation among various techniques. There was a significant reduction in oil content of the potato crisps observed when the new techniques were applied. The crisps that had been pre-treated and fried with conventional frying have given the result of 30 wt % reduction. The crisps that were fried under vacuum frying achieved greater oil reduction with varying percentages when applying different pretreatments. The lowest oil content was achieved when the potato crisps were fried at 110oC and 150 mbars giving 58 % reduction on the dry basis compared with control samples. There are various advantages of the technique with PSSD as we have discovered: it is simple and can be applied in potato crisp industries in continuous mode in both vacuum and conventional frying systems. The crisps that had been treated with pre-drying and subsequent sugar solution dipping and then fried were crunchier and possibly had better perceived taste to the consumer, due to the small sugar addition. Pre-drying and vacuum frying have all turned out to be excellent techniques to reduce acrylamide formation in potato crisps as we have found in this study. Vacuum frying at 120oC and 150 mbars reduced acrylamide formation by 80 to 85%. The 95% reduction was obtained when the crisps had been pre-dried. Acrylamide was undetectable when crisps were pre-dried and vacuum fried at 110oC, 150 mbars. The crisps with pre-drying subsequent sugar dipping and vacuum fried at low temperature had improved color compared with the control samples, which were produced by conventional frying at high temperatures. / Note: Part 3 publication restricted due to copyright restrictions.

Reducing oil content, minimizing any carcinogenic acrylamide in the high temperature frying process for potato crisps, and producing good products with considerable crispiness and acceptable color were the objectives of this research. Vacuum frying with pre-treatment of potato crisps was investigated as an effective process for oil content reduction. Pre-drying and subsequent dipping (PSSD) in a sugar solution (‘sugar dipping’) were considered as an advantageous procedure for the treatment of potato crisps before frying in order to reduce oil uptake during frying. Vacuum frying was observed as an excellent process to decrease significantly the acrylamide formation at low temperature frying of potato crisps. In this study, potato crisps were respectively blanched, pre-dried, and dipped in a solution of sugar (23.07 wt %) for two seconds, before vacuum frying at 120oC, 110oC under different vacuum pressures (170mbars, 150mbars, 100mbars and 50mbars in separate experiments). Conventional frying at 180oC was also used as the control to benchmark the reductions in the oil contents and acrylamide formation among various techniques. There was a significant reduction in oil content of the potato crisps observed when the new techniques were applied. The crisps that had been pre-treated and fried with conventional frying have given the result of 30 wt % reduction. The crisps that were fried under vacuum frying achieved greater oil reduction with varying percentages when applying different pretreatments. The lowest oil content was achieved when the potato crisps were fried at 110oC and 150 mbars giving 58 % reduction on the dry basis compared with control samples. There are various advantages of the technique with PSSD as we have discovered: it is simple and can be applied in potato crisp industries in continuous mode in both vacuum and conventional frying systems. The crisps that had been treated with pre-drying and subsequent sugar solution dipping and then fried were crunchier and possibly had better perceived taste to the consumer, due to the small sugar addition. Pre-drying and vacuum frying have all turned out to be excellent techniques to reduce acrylamide formation in potato crisps as we have found in this study. Vacuum frying at 120oC and 150 mbars reduced acrylamide formation by 80 to 85%. The 95% reduction was obtained when the crisps had been pre-dried. Acrylamide was undetectable when crisps were pre-dried and vacuum fried at 110oC, 150 mbars. The crisps with pre-drying subsequent sugar dipping and vacuum fried at low temperature had improved color compared with the control samples, which were produced by conventional frying at high temperatures. / Note: Part 3 publication restricted due to copyright restrictions.

<p>The farming of insects has been shown to require less land, feed, and water compared to traditional livestock maintenance, while proven to be a source of high-quality protein. The aversion of the Western culture towards edible insects is the major hurdle into their incorporation in the market, unveiling the challenge of integrating them into an existing familiar product. However, studies have shown that merely pulverizing insects into edible “flours” possesses difficulties on itself such as low solubility; severely altering the structural and sensory characteristics of food products upon their addition. Alternatively, scientists have turned to chemical protein isolation techniques to create insect flours with improved functionality. Furthermore, enzymatic proteolysis has shown to aid in extracting the protein bound to insoluble chitin and enhancing techno-functional properties. While this promising technique may open a range of possibilities, no research has been done regarding the incorporation of insect hydrolysates into a food matrix. The purpose of this work was to explore the production of insect hydrolysates with improved techno-functional properties and their impact in the physicochemical, structural, and sensory characteristics on a chosen model matrix: corn tortillas. Crickets (<i>Acheta domesticus</i>) were chosen due to their current relevance in the Western market. </p> <p>Hydrolysates were produced with low (5%), medium (8%), and high (15%) degrees of hydrolysis (DH) either with Alcalase (AL) or Flavourzyme (FL). Alcalase cricket protein hydrolysates (CPH) resulted in higher fat content, which was suspected of possessing surface-activity. Overall, AL peptides displayed significantly (p < 0.05) higher emulsion and foam capacity and stability, suggesting stronger amphiphilic activity. On the other hand, FL peptides were more soluble and had a lower mean molecular weight, demonstrated by their lower glass transition temperatures. Both of these developments may be explained by Alcalase endopeptidase activity and Flavourzyme primarily exopeptidase activity. Treatments resulted in AL-peptides with large and medium size molecular weights that included hydrophobic terminal ends, while FL peptides were smaller and likely contained free amino acids. The difference in molecular weights were seen upon their addition in the raw corn masa, where AL-CPH increased elastic and viscous behavior compared to control, whereas the smaller FL-CPH lowered them due to the plasticizing capability of hydrophilic small peptides. The ability of FL-CPH to interact with corn macromolecules was observed upon thermal treatment, resulting in FL-tortillas with superior strength and extensibility compared to AL-tortillas. In fact, AL-tortillas fragility was seen by the rollability test, showing a complete disintegration of the tortilla structure. Raman spectroscopy further showed the heat-induced intermolecular interactions of FL-peptides with the corn macromolecules. Raman bands at 1049 cm^-1 in FL-tortillas allude to protein-starch complexes and the <i>gauche-gauche</i> region confirmed the presence of disulfide bridges in FL-tortillas, both of these developments were absent in AL-tortillas. Lastly, the formulation of corn chips with these CPH proved to be globally accepted by a population with diverse neophobia levels, confirming theories that consumers are willing to eat insects in an “invisible” format. Flavor and aroma profiles of the chips, quantified by a descriptive analysis study, revealed no commonalities between the two sets of chips. AL-chips were characterized as having corn, shrimp, and roasted peanut notes, while FL-chips were characterized as having tomato, ketchup, and French fry notes. Overall, enzymatic proteolysis was shown to generate cricket peptides with different characteristics, both able to be utilize as a functional ingredient for palatable food products. </p>

<p>  </p> <p>  The effects of science have remarkably changed our world and we should learn how to live effectively in a consistently evolving world. Scientific thinking is believed to be the key factor in developing the ability to use scientific knowledge in problem-solving (Norris & Philips, 2003; Zimmerman, 2000). Therefore, increasing adults’ ability to think scientifically would help them apply better problem-solving strategies in everyday routines. Unfortunately, not a lot has been done on advancing scientific thinking education among adults in formal and nonformal educational settings in the U.S. (Osborn, 2013). Hence, this study used case study approach, a qualitative research method, to explore Purdue Extension Master Gardener volunteers’ scientific thinking in the context of problem-solving through inquiry. The purpose of this study was to explore Purdue Extension Master Gardener volunteers’ scientific thinking throughout a home hydroponics inquiry-based project and to describe their experiences to complete the learning module. This study took over nine weeks of a virtual inquiry-based learning program with four Purdue Extension Master Gardener volunteers. Data collection included pre- and post-interview, project worksheets and exit notecards at the end of each online lesson.</p> <p>  </p> <p>There were three major findings. First, participants demonstrated scientific thinking skills by conducting experiments and acknowledging the effectiveness of scientific inquiry in problem-solving. Second, participants’ learning experiences were positive following the integration of adult learning theory assumptions into the learning module. Third, participants expressed intent to continue using scientific experiments to solve their gardening problems as a new skill they learned and found effective in helping them understand and solve problems. The findings of this study suggest that both domain-specific (prior knowledge and everyday life experience) and domain-general (scientific methods and reasoning processes) strategies are important to conduct scientific reasoning. In addition, motivation is a critical factor that drives the direction of inquiry, hypothesis, and helps in persisting to finish up the experiments. The findings also suggested that adults learn best when they have independence and self-direction in working on topics that align with the real-world problem-solving directly linked to their everyday life. </p> <p>  </p> <p>The findings of this study suggest that developing scientific thinking increases the ability of adults to appreciate valuable information, evaluate data source, and increase informed citizenry in general. Also, for teaching adults, instructors and instructional designers should concentrate on topics that have direct impact on adults’ life, mainly focusing on real-world problem-solving. Future studies could consider exploring scientific thinking using a different context than problem-solving used in this study. Future studies also should consider using larger populations with a variety of backgrounds to assess the role of prior knowledge in scientific thinking development. </p>

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.