Formation of anaerobic products in sweet cherries and their partial release into ambient atmosphere under low oxygen storage

Concentrations of acetaldehyde, ethanol and ethyl acetate in the flesh of ripe, sweet cherries were consistently enhanced by very low oxygen conditions in the ambient atmosphere. At the onset of storage the initial concentration of ethanol in the flesh was 6.0 and 6.4 mg l-1 for the cvs. 'Kordia' and 'Vanda' respectively. After 28 days under anaerobic conditions the concentration in the flesh of cv. 'Kordia' was 5,502 ± 35 mg l-1, which during the next 10 days of storage in air was increased to 6,476 ± 771 mg l-1. The production of ethanol under anaerobic conditions increased during the storage period from 101 μg kg-1h-1 to 550 μg kg-1h-1 from the 16th to the 27th day. The ethanol released from fruit stored at ULO and CA atmospheres was accumulated in the ambient atmosphere at very low concentrations, two orders lower than in the anaerobic atmosphere, at concentrations from 1.2 to 1.6 μg kg-1h-1. The concentration of ethyl acetate during the first 10 days under very low oxygen atmosphere did not increase, because biosynthesis practically ceased. At the start it was 0.76 mg l-1 and after 10 days it had increased to only 0.88 mg l-1. Until the fruit is exposed to a normal supply of oxygen from the air, there is no change in the esterification rate. Some quantitative relations relate to the production and subsequent release of ethyl acetate from intact fruit, which under subsequent ambient atmosphere storage was detected at very low trace concentrations, of 20 to 80 nl l-1 overall, for all the different storage regimes

Volatiles Distinguishing the European 'Conference' and the Asian 'Yali' Pears Stored at Different Post-Harvest Temperatures

A total of 124 identical volatile aromatic compounds were identified during storage of the European 'Conference' and the Asian 'Yali' pear cultivars in different temperature conditions. Only 5 volatiles were statistically differentiated in both cultivars by means of successive multinomial logistic regression: 3-methylbutan-1-al, 2-methylpropyl acetate, 2-methoxy-4-vinylphenol, ethanol, and eugenol. Significant statistical data obtained by sequential multinomial logistic regression developed by the principal component analysis (PCA) procedure and distinguishing the different 'Conference' and 'Yali' pears storage regimes were dimensionless in themselves. The PCA components were expressed as linear combinations of selected variables necessary to distinguish the cultivars. The eigenvalues of the first three PCA components differentiated the storage regimes. For each principal components were selected volatiles with a probability higher than 0.4. Combinations created from PCA components were shown using clusters distinguishing the pear storage conditions used. Analytical data from SPME-GC/MS such as concentration (ng kgMINUS SIGN 1) demonstrated multiple and order-of-magnitude differences between the 'Conference' and 'Yali' pears. The 'Yali' cultivar exhibited significantly higher concentrations of eugenol.O

Comparison of the influence of defined storing conditions on asian and european pear cultivars

The study observed changes in the material composition of European (Conference) and Asian (Yali) pears during the storage period at different temperatures. Three different temperatures were selected for storing, i.e. 1 °C, 5 °C and 20 °C. Assessed for each of the pieces of fruit were flesh firmness, titratable acidity, soluble solids content, content of organic acids, and production of ethylene and carbon dioxide. Fruit stored at 1 °C and 5 °C was analysed before the moment of putting to the store and then after 25, 55 and 70 days of storing. Fruit stored at 20 °C was analysed before the moment of putting to the store and then after 14, 22 and 30 days of storing. The respiration intensity observed through carbon dioxide production at refrigeration conditions was approximately of the same progress for both of the varieties. For the Yali variety, the intensity of respiration of the fruit at the start of the storing period strongly decreased.The same progress was recorded for the Conference variety. Storing at 20 °C increased the respiration intensity. The varieties Yali and Conference which were stored under the temperature of 5 °C had the highest CO2 production after 70 days of storage. For both varieties the lowest ethylene production during storage was observed at 1 °C. Ethylene production was higher in Yali pear fruits. The Yali variety stored at 20 °C from the beginning produced up to 10 times higher concentration of ethylene than the fruit of the Conference variety. The highest amount of ethylen by the Conference variety was produced by the fruits which were stored under the temperature of 5 °C. At the beginning of the storage period the Conference pears had two-fold higher flesh firmness than the Yali fruit. Fruits of the varieties Yali and Conference which were stored 70 days under the temperature of 1 °C had the highest flesh firmness. For soluble solids and titratable acidity no clear progress was recorded. Malic acid was predominant in both varieties. The Yali fruit contained more citric acid than the Conference fruit. In both varieties soluble solids gradually increased in the early days of storage at all of the monitored temperatures

The effect of post-harvest treatment on the quality of sweet cherries during storage

Cherries are a traditional commodity grown in the Czech Republic. Placing into a cold room is essential for the fruit to be preserved in the long term. Even if optimum storage conditions are followed, the shelf life is relatively short. This study observed the effect of packing cherries into the Xtend polymer wrap on slowing down the degradation of the fruit during the storage period. The experiment was conducted using 4 varieties of the sweet cherry (Prunus avium L.) from the identical site (Stošíkovice, Czech Republic) - 'Vanda', 'Kordia', 'Sweetheart' and 'Regina'. Part of the fruit was stored at 20 °C for 7 days (conditions in retail chains) and other part of the fruit was stored at 1 °C for 50 days, first half of fruit was stored in Xtend polymer wrap and second half in the normal air conditions. Changes were also investigated in fruit quality parameters (soluble solids, titratable acidity, weight loss, peel firmness and respiration intensity) under the shelf life conditions when the fruit was placed at the distribution temperature of 20 °C after removal from the store and analysed after 5 and 10 days. Packed fruit exhibited significantly lower weight loss than unpacked fruit. Unpacked fruits showed visible signs of wilting and it is connected to the water loss and loss of turgidity of fruit. Soluble solids content and titratable acidity reduced generally less in unpacked fruit, which was probably related to the higher weight loss in this variant. Between the packaged and control fruit firmness was not statistically significant. Carbon dioxide production characteristic the intensity of respiration was typically higher at 1 °C for fruit packed in the Xtend film. This fruit, however, largely responded by reducing the intensity of respiration when removed from the store and placed at 20 °C, whereas in unpacked fruit there was a several-fold increase in carbon dioxide production under such conditions

Optimal Tolerogenic Dendritic Cells in Type 1 Diabetes (T1D) Therapy: What Can We Learn From Non-obese Diabetic (NOD) Mouse Models?

Tolerogenic dendritic cells (tolDCs) are explored as a promising standalone or combination therapy in type 1 diabetes (T1D). The therapeutic application of tolDCs, including in human trials, has been tested also in other autoimmune diseases, however, T1D displays some unique features. In addition, unlike in several disease-induced animal models of autoimmune diseases, the prevalent animal model for T1D, the NOD mouse, develops diabetes spontaneously. This review compares evidence of various tolDCs approaches obtained from animal (mainly NOD) models of T1D with a focus on parameters of this cell-based therapy such as protocols of tolDC preparation, antigen-specific vs. unspecific approaches, doses of tolDCs and/or autoantigens, application schemes, application routes, the migration of tolDCs as well as their preventive, early pre-onset intervention or curative effects. This review also discusses perspectives of tolDC therapy and areas of preclinical research that are in need of better clarification in animal models in a quest for effective and optimal tolDC therapies of T1D in humans

Proteomics in food: Quality, safety, microbes, and allergens

Food safety and quality and their associated risks pose a major concern worldwide regarding not only the relative economical losses but also the potential danger to consumer's health. Customer's confidence in the integrity of the food supply could be hampered by inappropriate food safety measures. A lack of measures and reliable assays to evaluate and maintain a good control of food characteristics may affect the food industry economy and shatter consumer confidence. It is imperative to create and to establish fast and reliable analytical methods that allow a good and rapid analysis of food products during the whole food chain. Proteomics can represent a powerful tool to address this issue, due to its proven excellent quantitative and qualitative drawbacks in protein analysis. This review illustrates the applications of proteomics in the past few years in food science focusing on food of animal origin with some brief hints on other types. Aim of this review is to highlight the importance of this science as a valuable tool to assess food quality and safety. Emphasis is also posed in food processing, allergies, and possible contaminants like bacteria, fungi, and other pathogens

Characterization and identification of wheat allergens from foodstuffs containing wheat

In some cases, ordinarily accepted food can evoke harmful clinical symptoms which are brought on by sensitivity on specific component of foodstuff. This harmful reaction on accepted food is called food allergy and it tends to go up in the world's population in last years. The food allergy affects especially children as well as adults. The important role in the food allergy plays wheat and foodstuff containing components of wheat. Wheat allergens from flour is already well-known, but man accepts wheat in food in the treated form (heat treated food) what can decrease or increase allergenicity. Moreover, enzymes presented in gastrointestinal tract of man can influence allergenicity of wheat allergens too. The goal of this thesis is characterization of allergens presented in heat treated wheat foodstuff and in wheat foodstuff digested by enzymes in gastrointestinal tract of man. Characterization of these altered and newly produced allergens can help find better diagnostic techniques, increase specificity of detection of IgE antibodies, enable pointed therapy of allergic patients or find and apply new and suitable diet