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31.
冬枣采后生理及贮藏技术研究 总被引：9，自引：1，他引：9
研究了不同温度和不同气体条件下冬枣的贮藏效果，不同温度下枣果实呼吸强度的变化，以及在贮藏期间枣果实Vc、总糖、乙醇、丙二醛(MDA)含量的变化。结果表明：冬枣采后呼吸强度很高，但属于非呼吸跃变型果实；随着贮藏期的延长，枣果Vc含量逐渐减少，总糖含量前期升高，中后期逐渐下降，乙醇和MDA含量逐渐升高；低温气调贮藏效果明显好于单纯的冷藏，气调贮藏对提高Vc的保存率、保护细胞膜系统、延缓果实衰老有明显的作用，并不会加重枣果实的无氧呼吸而使乙醇生成量增加。 相似文献
32.
《Food Control》2017
Postharvest losses in fresh produce chains are a major threat to food security, especially in transition countries. To develop effective intervention strategies for postharvest losses reduction, it is important to first understand the core logistics and quality control activities that could affect postharvest losses in these chains. In this study, a diagnostic tool was developed and used to assess the implementation level of core logistics and quality control activities, the vulnerability of the system due to the context in which it operates, and the actual postharvest losses. Based upon a literature review, the context characteristics are divided into product, process, organisation, and supply chain environment characteristics to assess the context vulnerability to postharvest losses. The identified core logistics activities are planning on the amount of fresh produce to harvest and process, selecting issuing policies, selecting mode of transportation and type of vehicle, and vehicle scheduling and routing. Maturity determination at harvest, deciding on harvest moment, harvesting, packing, and storage practices, use of grading standards, package material, temperature monitoring during storage and transportation, and equipment maintenance are the core quality control activities identified. The tool was applied to three groups of farmers operating in a tomato supply chain in Zimbabwe. The major findings are that commercial farmers recorded lower postharvest losses (1%) as compared to subsistence farmers (3%), the context for commercial farmers is less vulnerable to the generation of postharvest losses as compared to that for subsistence farmers, and logistics and quality control activities for commercial farmers are implemented at a more advanced level. The tool provides differentiated assessment that allows users to identify improvement opportunities to achieve higher performance for the activities and to reduce context vulnerability. 相似文献
33.
Stilbene-enriched wine is considered an interesting new food product with added value as a consequence of the numerous health-promoting properties ascribed to it, mainly from its trans-resveratrol content. Postharvest grapes have been treated with ultraviolet-C light to produce stilbene-enriched grapes that were later used in a conventional winemaking process to obtain a red wine enriched in stilbenes. 相似文献
34.
Combined microwave and hot-air drying characteristics was studied for the drying of cranberries that had been previously partially dehydrated by osmosis in a high fructose corn syrup (76°Brix). A 750 W 2450 MHz microwave oven was used to dry cranberry samples from 57% to 15% moisture content using three different power densities (0.75, 1.0, 1.25 W/g of initial cranberries) and two different power cycles (30 s On/30 s Off and 30 s On/60 s Off). All combinations of these variables were tested in triplicate. Quality of the cranberries was measured using a universal testing machine, chromameter, and with the use of a taste test panel. Drying times ranged from 2.2 to 5.0 h. Power times and power cycles affected the drying time and the quality of the dried cranberries. Lower power densities resulted in cranberries with higher quality. High power densities (125 W/g) resulted in the burning of some cranberries. 相似文献
35.
Xueyan Ren Qingjun KongHuili Wang Ting YuWen-Wen Zhou Xiaodong Zheng 《Food chemistry》2012,131(3):796-801
Cecropin A gene was cloned into the expression vector pPIC9k and was successfully expressed in methylotrophic yeast, Pichia pastoris GS115. The yeast had effective antimicrobial activity on Geotrichum citri-aurantii spores by the thiazolyl blue (MTT) assay. There was no large growth difference between nontransformed strain GS115 and recombinant strain GS115/CEC in citrus fruits wounds. Yeast transformants could significantly inhibit growth of germinated G. citri-aurantii spores and inhibited decay development caused by G. citri-aurantii in citrus fruits compared to the yeast strain GS115/pPIC. This study demonstrates the potential of expression of an antifungal peptide in yeast for enhancing suppression of postharvest diseases and represents a new approach for the biological control of postharvest diseases. 相似文献
36.
本论文以中华寿桃为试验材料,研究了不同贮藏条件对中华寿桃的冰点、呼吸强度、VC含量、相对电导率、PPO等品质和生理指标的影响.并探讨了中华寿桃软化衰老的生理机制,为中华寿桃的贮藏保鲜提供了理论依据. 相似文献
37.
The effect of Rhodotorula glutinis treatment alone or in combination with methyl jasmonate (MeJA) in controlling blue mold decay, the natural fungal decay of pears and the postharvest quality parameters including fruit firmness, total soluble solids, titratable acidity, and ascorbic acid were investigated. The combination of methyl jasmonate (200 μM) and R. glutinis (1 × 108 CFU/ml) was a more effective approach to reduce the disease incidence and lesion diameter of blue mold decay of pears than the application of MeJA or R. glutinis alone after incubation for 7 d at 20 °C. The natural fungal decay of pears treated with the application of R. glutinis combined with MeJA resulted in reduced average decay incidence of 10.42% or 4.16%, respectively, compared with 27.17% or 20.83% in the control fruits following storage at 20 °C for 15 d or 4 °C for 60 d followed by 20 °C for 15 d. The combined treatment did not impair quality parameters of fruits under both conditions. 相似文献
38.
Bundit Jarimopas Phanida Pushpariksha S. Paul Singh 《International Journal of Food Properties》2013,16(2):414-426
Postharvest damage in fresh mangosteens at wholesale level in Thailand was investigated from April to October 2004. A total of 37.1% of the production yield was rendered inedible by damage during this period; damages included fruit cracking, hardened rinds, rough surfaces, translucent flesh, gummosis and decay. This study focused on a method of predicting damage based on the color of the skin of the affected mangosteen. As a first step, diameter, height, weight, and volume of large, medium, small, and undersize mangosteens were measured. The term, dimension ratio, was introduced as a sizing parameter identifying conventional trade size. The coefficient of static friction of the glossy- and rough-surface mangosteens on plexiglass, plywood, and galvanized steel sheet varied from 0.31 to 0.46. The color of sound and defective fruits was measured in terms of their tristimulus values X, Y, and Z. The corresponding chromaticity coordinates of a mangosteen, x and z, depended on the maturity stage of the fruit while y depended on the type of fruit surface. A ratio was proposed to test the accuracy of predicting internal defects from the color variation between two spots on the surface of the same fruit. The highest percentage of correct prediction was 67.4% with a color ratio of X1 (pink blush color on yellow ground color) to X2 (pink color) that was greater than 1.25. 相似文献
39.
Hermetic storage containers are often used by farmers to protect their harvested grain from insect damage and ultimately stop insect population development. Sometimes holes in a storage container are created by insects or by accident; such holes may reduce the effectiveness of the hermetic storage unit. Using cowpea grain and the cowpea bruchid, Callosobruchus maculatus (F), we investigated the degree to which holes in a hermetic storage container wall affect the level of grain damage. When there were low numbers of holes, seed damage increased markedly with each additional hole. The grain itself contributed a barrier to oxygen diffusion through the grain mass. If holes in the container wall were patched with a single layer of HDPE film, grain damage was indistinguishable from that seen under full hermetic conditions. We provide evidence that a single layer of woven polypropylene contributes a small but measurable barrier to oxygen penetration into the container. 相似文献
40.
Rice is the world's most important staple food and the basis of the diet of the majority of the population. In small farm agriculture, the yields obtained in cereal production are usually low and losses, both in the field and during storage, are dramatically high, particularly in developing countries. In Mozambique, these aspects, together with an increased frequency of floods, are hindering advances in rice production. Aimed at contributing to the reduction of losses in stored rice, trials were carried out to compare the effectiveness of traditional raffia bags and of hermetic storage using single and double plastic bags concerning quantitative losses and seed quality, including germination potential, after three and six months of storage. Pest identification, insect populations estimates, percentage of weight loss, germination power and seedling vigor were evaluated. The results showed that, in descending order of density, Angoumois grain moth (Sitotroga cerealella Olivier), lesser grain borer (Rhyzopertha dominica F.), rice/maize weevil (Sitophilus zeamais Mostch. and Sitophilus oryzae L.) and red flour beetle [Tribolium castaneum (Herbst)] were the main insects infesting the rice. When compared to hermetic storage with both single and duplicate airtight bags, traditional storage presented statistically significant higher mean infestation density (30.63–53.94 individuals/kg in traditional and 0.71–3.50 individuals/kg in hermetic storage) and percentage of weight loss (3.03–3.44% in traditional contrasting with 0.27–0.47% in hermetic conditions). In traditional storage a significant 38.25% drop in the germination potential was also observed, attaining values below the established minimum tolerated in Mozambique (80%), while under hermetic storage, that reduction remained within the acceptable values of 13.9–17.5%. The distinct storage methods did not produce significant differences on the moisture content of the grain. These results demonstrate that the use of hermetic storage has resulted in a safe, pesticide-free, and sustainable storage method, suitable for rice seeds, with advantages over traditional bagging. The results presented here lead to propose hermetic storage to be adopted by paddy small farmers, in order to lever food security and income generation in the country. 相似文献