This research evaluates the effectiveness of using carbon dioxide (CO2) pressurization to extend strawberry fruit prep shelf life for the eventual use in yogurt applications. In this experiment, CO2 treatments of 5, 15, and 25 pounds per square inch were used as a processing step to inactivate microorganisms, which in turn could aid in the preservation and maintenance of product quality during storage thus improving consumer acceptance of the yogurt. Microbial levels of the fruit prep treatments were monitored over a six-week period by enumerating aerobic plate counts and yeast and mold levels. The color, pH, and texture of the treatments were also evaluated throughout the duration of the study. Sensory attributes of the product were evaluated by formal sensory panel at the beginning of the study to gather consumer feedback on potential changes introduced by the treatment to the finished product. For sensory analysis, the different CO2 treatments of fruit prep were mixed with plain yogurt and given to panelists. The different treatments were taken from one homogenous mixture of fruit prep and then were randomly divided into five different treatment groups: a control group, a thermally processed group, and the three different pressure levels of CO2. Results from the experiment showed that carbonation does not negatively impact product overall acceptability. Shelf life results showed that CO2 treatments are not effective in maintaining or extending the shelf life of strawberry fruit prep when compared to a thermal treatment.

It has been well documented that fruit and vegetable (F/V) intake is linked to lower risk of mortality and chronic disease. Raman resonance spectroscopy is a valid indicator of F/V intake and quantifies that intake by measuring skin carotenoid levels. In this study, 46 children, participated in a 6-week feeding study wherein they were randomly assigned to one of two groups: 1) consuming a high-carotenoid (HC) breakfast/snack food, or 2) consuming a placebo bar, every day. The HC food contained 4.3mg carotenoids per serving and the placebo contained none. Skin carotenoids were measured every two weeks using a BioPhotonic scanner. The treatment group had a mean increase in scanner score of 5,802 Raman intensity units which was significantly higher than the mean increase of the placebo group, 1,771. In this study we found that consumption of 120 gm of a high-carotenoid food significantly increased skin carotenoid levels in children ages 5-18 over a 6 week period. Packaging type as well as storage conditions play a role in preserving carotenoids which are sensitive to light, temperature, and oxygen. Care must be taken when choosing packaging and storage conditions for foods containing carotenoids. Two shelf-life studies, one at room-temperature and another in frozen storage, were conducted on the HC breakfast/snack food to determine the best method of packaging to maintain quality and preserve carotenoids. The food was randomly packed into one of three packaging types for both studies. The packages used in the frozen study were then randomly assigned to one of three freezer storage methods. Room-temperature samples were analyzed on days 3, 7, 10, and 14 and samples in frozen storage were pulled every month for 5 months. Measures of water activity, moisture content, color values (L*a*b*, chroma, and hue), and carotenoid content were analyzed in each sample. At the conclusion of each study, L*, b*, chroma, and hue were significantly affected by packaging type. No significant associations were found in any other measures. From this study we draw the conclusion that cellophane packaging or packaging with a N2 backflush would be the best options for use with this food to best retain its quality.

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No description available.

Shrimp is the most valued shellfish product in the United States, and is highly perishable with post mortem metabolic changes that are deteriorative to its shelf-life. The objective of this research was to utilize GC-MS Gas Chromatography-Mass Spectrometry (GC-MS), Gas Chromatography Olfactometry (GCO), and sensory analysis to determine if the relationships exist between consumer acceptability, sensory descriptors and shelf-life of ready-to-eat shrimp. Three different cooking and packaging treatments were utilized: 63°C/15 s, 85°C/5 min, and 93°C/5 min for vacuum, MAP and aerobic packaging treatments, and stored at 2°±1 for 1, 3, 5, 6, 10, 15, 25, and 50 days or until the product was found unacceptable by a trained sensory panel. For Consumer acceptability (Day 3), the 85°C vacuum and 85°C MAP (Modified Atmosphere Packaging) shrimp were preferred (P < 0.05) over other treatments that were evaluated. The aroma active compounds that were identified using GC-MS and GCO consisted of one amine (trimethylamine), five aldehydes (3-methyl butanal, pentanal, hexanal, heptenal, geranial), one organic acid (butyric acid), two sulfur containing compounds (methional, dimethyltrisulfide), one pyrazine (methyl pyrazine) (amine), two alcohols (2-nonen-1-ol, 4 ethyl guaiacol), and one hydrocarbon (camphene). Results showed that for most of the packaging-temperature combinations, even beyond Day 25, the MAP product had fewer compounds and odors associated with spoilage than the aerobic and vacuum packaged products. This was consistent with the descriptive analysis data for which both the 85°C MAP and 93°C MAP treatment products had a longer shelf-life than vacuum treatment products, which had shelf-lives of 15 to 21 Days. The shelf-life of the cooked RTE shrimp that was MAP packaged and cooked at either 85°C or 93°C was between 39 and 42 Days at 2°C. Research indicates that processors of medium gulf brown shrimp could utilize 85°C/5min with MAP due to the shelf-life of the product and the elevated pleasantness scores when compared to the 93°C/5min treatment throughout the shelf-life of the product.

Edam and Cheddar whey were thermized (T) for different time periods (5–30 min) at 70 degrees Celsius, vacuum evaporated, and spray dried to obtain whey powders (WP). Native and thermized WP were evaluated for antioxidative properties. Edam and Cheddar WP significantly reduced thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV) in ferric-catalyzed soybean oil emulsions. Thermization significantly improved antioxidative properties of WP with 5T, 10T, and 15T treatments showing better protective effects compared to 20T and 30T treatments. Based on these results, native (0T) and thermized (5T, 10T, and 15T) Edam and Cheddar WP coatings, with and without enzymatically hydrolyzed casein (CH), were used to reduce oxidative degradation and moisture loss of cubed beef steak and pork loin. Thermized treatments significantly reduced TBARS and PV in both types of meat, with CH containing treatments showing enhanced antioxidative properties. Protein oxidation as reflected by carbonyl formation and a decrease in sulfhydryls was also reduced by thermization. Treated and native WP coatings significantly reduced moisture loss of meat samples. Cubed beef steak treated with Cheddar WP coatings were evaluated for microbiological quality and basic sensory attributes. Although not statistically significant, 5T, 10T, and 10TCH treatments numerically showed potential for microbial reduction up to 4 days of storage. Sensory evaluation showed significant protection of key sensory attributes by treatments throughout the storage period when compared to controls with the 5 min thermization showing the best effect on lowering offlavor development based on sensory scores. The effect of pH and glucomannan (GM) on antioxidative properties of thermized (5T) Cheddar WP coatings applied to catfish fillets was also investigated. Coatings at pH 7.0, 7.5, and 8.0 (with GM) showed markedly greater protection against oxidative degradation compared to coatings without GM, as reflected by TBARS values and PV after 7 days of storage. Carbonyl formation and oxidation of sulfhydryl groups were also significantly reduced by coatings containing GM. Cheddar WP-based edible coatings (pH 7.0–8.0) with GM markedly reduced lipid oxidation and protein oxidation of fresh catfish fillets.

Thesis (Ph.D.(Microbiology)) -- University of Limpopo, 2022 / Traditional sorghum juice is produced in many African countries for human consumption. The juice is very rich in calories, B-group vitamins including thiamine, folic acid, riboflavin, nicotinic acid, and essential amino acids such as lysine. Low earning income women at village level produce sorghum juice for home consumption and sale. The short shelf life (2 to 3 days) of sorghum juice is a major problem for both the brewers and consumers of this drink. The aim of the study was to use 12 Combretum plants to improve the microbiological quality and shelf life of sorghum juice. Fresh stems and leaves of C. caffrum, C. vendae, C. erythrophyllum, C. elaegnoides, C. apiculatum, C. imberbe, C. adenogdium, C. padoides, C. bracteosum, C. kraussii, C. mkuzense and C. zeyherii were collected at Nelspruit, National Botanical Gardens, Mpumalanga, South Africa. Voucher specimens and tree labels were used to verify the identity of the plants. The stems and bark collected were cut into pieces and air dried for 30 days. When dried, the plant material was ground to a fine powder and stored in paper bags at room temperature. The wood was burnt in an open fire; fuel was not used to minimise contamination. The qualitative phytochemical composition of both the leaves and stems of Combretum plants analysed in this study revealed the presence of saponins, tannins, terpenoids, steroids, cardiac glycosides and flavonoids. The following phytoconstituents were lost in the ashes; tannins with the exception of C. mkuzense and C. padoides; cardiac glycosides and flavonoids. The quantitative phytochemical analyses revealed that both the leaves, stems and some ashes such as C. apiculatum and C. vendae contained appreciable levels of phenolic compounds, tannins and flavonoids. Quantitative analysis of antioxidant activity, the 2, 2, diphenyl-1-picrylhydrazyl (DPPH) assay was used as a screen test for the radical scavenging ability of the compounds present in the different 36 70% acetone extracts. DPPH screening method indicated great scavenging activity with the 70% acetone leaf extracts of C. kraussii, C. zeyherii and C. mkuzense. The leaf and stem extracts showed substantial great antioxidant activity in a concentration-dependent manner. There was a significant decrease in the antioxidant activity in the ashes (p=001), when compared to both the leaves and the stems. The proximate and nutritional analysis of the 70% acetone extracts were performed by AOAC and ICPE protocols, respectively. The results indicated that all the extracts had substantial amounts of ash, moisture, protein and energy. Mineral content of the plant parts was analysed as well, calcium had the highest concentration, while zinc was lowest in concentration. The mineral content decreased significantly in the stems (p ≤ 0.05) when compared to the leaves. There was a further decrease in mineral content with regard to the ashes with the exception of calcium. Based on these findings, the leaves and ashes of C. adenogonium and C. apiculatum could provide a good source of calcium in the diet, while C. adenogonium, C. bracteosum and C. apiculatum had high levels of sodium. A serial micro-dilution assay was used to determine the minimum inhibitory concentration (MIC) values for 70% plant extracts using tetrazolium violet reduction as an indicator of growth. Two Gram-positive (Stapylococcus aureus ATCC 29213 and Enterobacter faecalis ATCC 29212) and two Gram-negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) bacterial strains were used in this study. The leaves had good antibacterial properties with the lowest MIC value being 0.04 mg/ml against E. coli and S. aureus. E. faecalis was found to be resistant against all the leaves with the exception of C. imberbe. The stem extracts of Combretum spp. tested in the study showed antimicrobial properties with the lowest MIC value being 0.04 mg/ml against E. coli shown by C. bracteosum. However, E. faecalis was resistant against all the 12 plants tested. All the test microorganisms showed resistance to the ashes, with the exception of S. aureus, which was found to be susceptible to 75% of the test ash extracts with the lowest MIC value of 0.16 mg/ml. Cytotoxicity and anticancer activity of the acetone extracts of the 12 Combretum plants were evaluated using tetrazolium-based colorimetric assay (MTT assay) on A549 lung carcinoma cells. The assays revealed that 50% of the leaf extracts of tested plants showed cytotoxicity and cell proliferation inhibition in A549 lung carcinoma cells in a concentration-dependent manner. The A549 cells were more sensitive to the following plants: C. elaegnoides, C. erythrophyllum C. imberbe, C. kraussii and C. mkuzense. The following stems extract, C. adenogdium and C. caffrum did not have any anticancer activity, whereas C. apiculatum and C. bracteosum were only able to reduce cell viability to less than 60%. C. mkuzense, C. padoides, C. vendae and C. zeyherii acted in a concentration-depended manner with the greatest activity seen at the highest concentration (1000 µg/ml). The plants had activity at concentrations between 31.25 and 1000 µg/ml allowing only 20% and 50%, respectively, of the cells to remain viable. Ashes from C. mkuzense showed good anti-cancer activity at the highest concentration (1000 µg/ml) reducing cell viability to around 10%. Enterobacteriaceae, total coliform, S. aureus, B. cereus, E. coli and lactic acid bacteria viability were studied during the four weeks storage period of prepared sorghum juices. Juice samples were collected after preparation; the samples were serially diluted using peptone water. Tempo instrument (Biomereiux) was used to enumerate total coliform, total aerobic count, E. coli, S. aureus, lactic acid bacteria, enteric bacteria, yeast and mould using the most probable number following the manufacturers instruction. C. mkuzense and C. padoides plants were able to inhibit the growth of B. cereus, lactic acid bacteria and S. aureus during the first three weeks of storage. E. coli was not present throughout the four weeks storage time. Vitek 2 Compact (Biomereiux) was used for the characterisation and identification of the dominant bacterial isolates using biochemical reactions. The isolates were characterised by morphological differences. Sixty five percent of the isolates were the Enterobacter genus that are commonly found in soil, water, and sewage. The nutritional composition and sensory properties of the prepared sorghum juices treated with Combretum plants were investigated. All the juices had appreciable amounts of protein, ash and energy. Sorghum juice treated with ashes of C. caffrum, C. erythrophyllum and C. kraussii had the highest levels of proteins when compared with other treated sorghum juices. The sorghum juices prepared in the study had varying levels of trace element or minerals with potassium -(3, 55 – 104 mg/l) and calcium (3.2-148 mg/l). Similarly, cobalt (-1.22), coppr (-0.99), iron(-0.962), magnesium (0.004), sodium (-0.145), nickel (-2.7)) and zinc (-1.2)are present in very low amounts. The juices treated with ashes had relatively higher levels of calcium, potassium, magnesium and sodium. Sorghum juices treated with the ashes had better sensory and organoleptic properties when compared with those treated with the leaves. The juices treated with the ashes of C. caffrum and C. bracteseum were more accepted by most of the panellist when compared with other treated juices. Overall, this study presents valuable information on the phytochemical composition, nutritional composition and antioxidant properties of some Combretum species in South Africa. It recommended its use as food and in pharmaceutical preparations for the local industries. In addition, Combretum plants showing the effects tested in this study may be explored further for development into drugs. functional food as food preservatives and nutraceutical applications, beside their traditional use / University of Limpopo and Foodbev SETA

Vegetable oil is an important commodity; however, the majority of commercially available vegetable oils have a fairly short shelf life, which limits their usefulness for long term food storage, disaster relief, space travel, food aid programs, and military rations. Vegetable oils with high oleic acid and reduced linolenic acid contents, especially with added antioxidant combinations, were previously found to have significantly longer oil stability index (OSI) values than traditional vegetable oils. This study used accelerated shelf life testing to estimate the ambient shelf life of high oleic sunflower oil (HOSUN) and high oleic canola oil (HOCAN), each containing 1,000 ppm ascorbyl palmitate, 200 ppm tertiary butyl hydroquinone, and 200 ppm mixed tocopherols. Oils were stored in the dark in low density polyethylene (LDPE), or polyethylene terephthalate (PET) bottles at 30, 40, 50, and 60°C. Control samples were stored in the dark in glass bottles at -50°C. Testing included peroxide values, qualitative headspace volatile analysis, descriptive sensory analysis, and consumer sensory acceptance. The estimated shelf life was calculated from the change in overall acceptance score over time using the Q10 method. The stabilized HOCAN in PET bottles was estimated to have a shelf life at ambient temperature of 6.8 years, while oil stored in LDPE bottles had an estimated shelf life of only 2.7 years. The estimated shelf life of HOSUN at room temperature in PET is 2.6 years and in LDPE is 0.88 years.

Protein bars have become a popular option among consumers to increase protein content in their diets. Since there is a large market for protein bars, many factors must be considered when creating a protein bar that both satisfies consumers and has a long shelf-life. Hardening and textural changes in protein bars are some of the most common modes of shelf-life failure in this product category. When the typical product creation timeline from formulation to launch can be as short as 3-6 months and with added pressure from executives to quickly launch another new product afterwards, product development scientists simply do not have time to test the full shelf life of their product before release. For this reason, it is imperative that rapid methods for detecting bar hardness and predicting shelf life of bar formulations are developed. The objective of this research is to utilize calorimetric techniques to rapidly detect and identify bar hardening reactions. Six different protein bar formulations were studied, with each containing a combination of either whey protein isolate (WPI), milk protein isolate (MPI), or partially hydrolyzed whey protein isolate (HWPI), reducing-sugar, non-reducing sugar, and vegetable shortening. All bars were stored at 45°C and ambient humidity for 21 d. Isothermal microcalorimetry (IMC) was used to evaluate bar hardening-related reactions and was compared to objective and subjective hardness measurements. Hardness, color, water activity, moisture content, and sensory evaluation were measured at d 1, 7, 14, and 21. The results of this study indicate that isothermal calorimetry may be used to narrow down bar hardening reactions and points to Maillard browning as a main driver of hardening. These techniques may be used to predict bar shelf life, if Maillard browning is used as the basis for hardening. Furthermore, this research highlights the importance of ingredient selection during bar formulation to minimize hardening.

The relationship among consumer acceptability, descriptive sensory attributes, and shelf-life was determined for 2 % milk pasteurized at 77, 79, 82, or 85?aC. Pasteurization temperature had no effect (p>0.05) on shelf-life. Consumers preferred (p<0.05) 79?aC over other treatments on day 0; however, six days post-pasteurization 79?aC milk was only preferred (p<0.05) over 77?aC. Consumers were grouped into eight clusters based on product liking for both day 0 and 6 evaluations. The largest cluster liked all pasteurization treatments, and 79?aC was highly acceptable to all consumers that liked milk. Similar sensory descriptors indicated the end of shelf-life for all pasteurization treatments even though treatments could be differentiated by descriptors on day 0. This research reveals that altering pasteurization temperature from 79?aC may cause a decrease in consumer acceptability to some consumers. Altering pasteurization temperature does not affect shelf-life or sensory descriptors and volatile compound profiles at the end of shelf-life.