Chilling-related postharvest rind breakdown of navel oranges is a significant economic problem worldwide. Chilling injury (CI) symptoms on navel orange fruit vary, and descriptive classification is generally ad hoc, making inter-study comparisons difficult. In this study, external symptoms of CI were related to patterns of cellular collapse in affected flavedo tissue, and a classification system developed to aid consistent symptom identification and improve communication within the supply chain. Potential markers of senescence were evaluated because older fruit were found to be more susceptible to CI. Electrolyte leakage, moisture content and protein content of flavedo tissue were ineffective indicators of both senescence and chilling stress. Rind colour and internal maturity were generally good indicators of fruit age, but lacked sensitivity over short time periods to be of use. Although there was a strong seasonal effect on CI incidence, pre-storage treatments, including hot water and methyl jasmonate, generally reduced the incidence of CI. Because these treatments elicit defence responses that protect tissue from chilling stress, the response and efficiency of plant defence systems is probably an important factor in chilling tolerance. The concentration of lipid hydroperoxides (LOOH) in flavedo tissue was lower in fruit that were stored at a chilling temperature (1�C) compared to fruit that were stored at a non-chilling temperature (12�C) and lipid peroxidation did not increase during storage at 1�C. There was also a lower concentration of LOOH in the chilling sensitive variety than in the chilling tolerant variety. Therefore, increased lipid peroxidation is not related to chilling stress and subsequent injury but the results do suggest a role for LOOH in stress signalling. Antioxidant activity in the lipophilic fraction of flavedo tissue extracts increased as fruit senesced and was strongly correlated with carotenoid content. LOOH concentrations in flavedo tissue also increased as fruit senesced. The antioxidant activity of both the lipophilic and hydrophilic fractions of flavedo tissue extracts was higher in fruit stored at 12�C than in fruit stored at 1�C.

Initial experiments were conducted to determine the microbial development in blocks of ground beef. In the top layers of the meat, Pseudomonas spp. predominated. Attempts were made, as well, to measure the microenvironmental changes occurring in ground beef using pH, oxygen, and redox potential micro-electrodes. / Some of the extrinsic (relative humidity, O(,2)), as well as intrinsic factors (pH, redox potential, ions, nutrients) affecting microbial development in aerobically stored meats, were examined. The decrease in glucose levels observed during the aerobic storage of longissimus dorsi (l. dorsi) muscle at 4(DEGREES)C, was accompanied by an increase in the activity of glucose dehydrogenase, and by the appearance of gluconate and 2-ketogluconate on the meat surface. / The attachment of various meat spoilage organisms to l. dorsi muscle was studied. Generally, the pseudomonads attached in higher numbers than the other bacteria, but possessed lower attachment strengths. Investigations on the attachment of two competing organisms to l. dorsi muscle demonstrated that limited competition occurs between the organisms. / A model of the microbial ecology of aerobically stored fresh beef was developed, based on existing evidence. / Various chemicals were added to minced or whole meat to evaluate their effectiveness as food preservatives. As a single compound, potassium sorbate appeared to have the greatest potential as a meat preservative. Meats > into solutions of 5.0% potassium sorbate for 1 min had their shelf-life substantially increased as compared with control samples > into water.

Pawpaw (Asimina triloba (L.) Dunal) has significant potential as a new fruit crop. During ripening, loss of firmness is extremely rapid, and this trait may be the biggest obstacle to the development of a broader market as handling without injury is difficult. Cold storage of pawpaw seems limited to 4 weeks at 4 C. A study of several cultivars with commercial appeal showed that ripening traits such as ethylene production, respiration and loss of firmness were similar in all genotypes, and that no cultivar showed superior responses to cold storage. Cold storage for longer than 4 weeks caused the development of cold injury symptoms such as black discoloration, rapid loss of firmness, impaired respiration, tissue acidification, decrease in antioxidant content, decrease in volatile ester production and development of off-flavor volatile compounds. Overall cold storage injury symptoms observed in pawpaw may be due to oxidative damage linked to the failure of the two major antioxidant systems that could protect against such damage: phenolics and the ascorbateglutamate system. With the aim of enhancing pawpaw low temperature tolerance and prolonging cold storage length, different techniques such as hot air exposure and hot water dips of fruit prior to beginning cold storage, and intermittent warming periods during cold storage, were evaluated. Despite positive results with these techniques for other commodities, all the strategies failed to appreciably alter fruit ripening, loss of firmness or maintain fruit quality during and/or after cold storage.

Chilling-related postharvest rind breakdown of navel oranges is a significant economic problem worldwide. Chilling injury (CI) symptoms on navel orange fruit vary, and descriptive classification is generally ad hoc, making inter-study comparisons difficult. In this study, external symptoms of CI were related to patterns of cellular collapse in affected flavedo tissue, and a classification system developed to aid consistent symptom identification and improve communication within the supply chain. Potential markers of senescence were evaluated because older fruit were found to be more susceptible to CI. Electrolyte leakage, moisture content and protein content of flavedo tissue were ineffective indicators of both senescence and chilling stress. Rind colour and internal maturity were generally good indicators of fruit age, but lacked sensitivity over short time periods to be of use. Although there was a strong seasonal effect on CI incidence, pre-storage treatments, including hot water and methyl jasmonate, generally reduced the incidence of CI. Because these treatments elicit defence responses that protect tissue from chilling stress, the response and efficiency of plant defence systems is probably an important factor in chilling tolerance. The concentration of lipid hydroperoxides (LOOH) in flavedo tissue was lower in fruit that were stored at a chilling temperature (1�C) compared to fruit that were stored at a non-chilling temperature (12�C) and lipid peroxidation did not increase during storage at 1�C. There was also a lower concentration of LOOH in the chilling sensitive variety than in the chilling tolerant variety. Therefore, increased lipid peroxidation is not related to chilling stress and subsequent injury but the results do suggest a role for LOOH in stress signalling. Antioxidant activity in the lipophilic fraction of flavedo tissue extracts increased as fruit senesced and was strongly correlated with carotenoid content. LOOH concentrations in flavedo tissue also increased as fruit senesced. The antioxidant activity of both the lipophilic and hydrophilic fractions of flavedo tissue extracts was higher in fruit stored at 12�C than in fruit stored at 1�C.

Thesis (M.S.)--Ohio University, March, 1995. / Title from PDF t.p.

Thesis (Ph. D.)--Columbia University, 1917. / Vita. "Scomber scombrus, was chosen as an ideal fish for an investigation of this sort."--P. 6. Bibliography: p. 22-24.

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017. / Food and water fuel and sustain life on earth. Since ancient times, their sourcing and preservation have been very important issues to humanity. In modern times, experimentation is a major step in analysing how cold storage problems in the medical and food science technology fields can be addressed. For investigating spoilage of new products and/or growth of pathogens in such cases, it is necessary to do experiments at different low temperatures for prolonged periods and check the effects. While this can be undertaken in a conventional two chambers fridge, it takes a long time to investigate a whole range of feasible storage temperatures. This dissertation describes work intended to treble the samples in such investigations and, therefore, significantly reduce the times. Six well- insulated chambers were constructed from plastic and wood and set at different temperatures. An ordinary deep freezer was used as the main heat sink for the chambers. Experiments were done with different methods to get the best result for the cold air flow into the chambers over period of eight months. The chambers temperatures were set between 0 and 15°C. It was finally established that a properly-designed six-chamber system could successfully be added to an ordinary freezer to provide different medium-to-high refrigeration temperatures without the use of a multi-pressure refrigeration cycle.

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