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991.
Methyl jasmonate reduces chilling injury and maintains postharvest quality of mango fruit 总被引:5,自引:0,他引:5
González-Aguilar GA Fortiz J Cruz R Baez R Wang CY 《Journal of agricultural and food chemistry》2000,48(2):515-519
Exposure of mango (Mangifera indica cv. Tommy Atkins) fruit to methyl jasmonate (MJ) vapors (10(-)(4) M) for 24 h at 25 degrees C reduced chilling injury during subsequent storage for 21 days at 7 degrees C and after 5 days of shelf life at 20 degrees C. The chilling tolerance induced by MJ was positively correlated with the reduction in the percent ion leakage of mango tissue. The overall quality of MJ-treated fruit was also better than that of control fruit. MJ treatment increased the total soluble solids but did not affect titratable acidity or pH. MJ also did not change the normal climacteric rise in respiration, water loss, and softening rates. The efficacy of MJ to reduce chilling injury and decay of mango could be related to the tolerance induced at low temperature. It was concluded that MJ treatment may prevent chilling injury symptoms of mango without altering the ripening process. 相似文献
992.
Ellagic acid, vitamin C, and total phenolic contents and radical scavenging capacity affected by freezing and frozen storage in raspberry fruit 总被引:9,自引:0,他引:9
The ellagic acid, total phenolic, and vitamin C contents in four raspberry cultivars (Heritage, Autumn Bliss, Rubi, and Zeva) grown in Spain were detected and quantified by HPLC in fresh, just frozen, and stored fruits at -20 degrees C for a one year period. Ellagic acid [207-244 mg kg(-)(1) of fresh weight (fw)], total phenolic (137-1776 mg kg(-)(1) of fw), and vitamin C (221-312 mg kg(-)(1) of fw) contents in raw material were higher in the late cultivars Zeva and Rubi than in the early cultivars Autumn Bliss and Heritage. The freezing process slightly affected the values of extracted ellagic acid, total phenolic, and vitamin C content. At the end of long-term frozen storage (12 months), no significant change of total phenolic content extracted was observed, but significant decreases of 14-21% in ellagic acid and of 33-55% in vitamin C were quantified. Free radical scavenging capacity measured as antiradical efficiency (AE) depends on the seasonal period of harvest. Late cultivars, Rubi (6.1 x 10(-)(4)) and Zeva (10.17 x 10(-)(4)), showed higher AE than early cultivars, Heritage (4.02 x 10(-)(4)) and Autumn Bliss (4.36 x 10(-)(4)). The freezing process produced a decrease of AE values in the four cultivars ranging between 4 and 26%. During the frozen storage, the AE values reached after the freezing process remained unchanged. 相似文献
993.
994.
Adsorption of whey protein isolate at the oil-water interface as a function of processing conditions: a rheokinetic study 总被引:4,自引:0,他引:4
Rodríguez Patino JM Rodríguez Niño MR Sánchez CC 《Journal of agricultural and food chemistry》1999,47(6):2241-2248
In this paper we present surface dynamic properties (interfacial tension and surface dilational properties) of a whey protein isolate with a high content of beta-lactoglobulin (WPI) adsorbed on the oil-water interface as a function of adsorption time. The experiments were performed at constant temperature (20 degrees C), pH (5), and ionic strength (0.05 M). The surface rheological parameters and the interfacial tension were measured as a function of WPI concentration (ranging from 1 x 10(-)(1) to 1 x 10(-)(5)% w/w) and different processing factors (effect of convection and heat treatment). We found that the interfacial pressure, pi, and surface dilational modulus, E, increase and the phase angle, phi, decreases with time, theta, which should be associated with WPI adsorption. These phenomena have been related to diffusion of the protein toward the interface (at short adsorption time) and to the protein unfolding and/or protein-protein interactions (at long-term adsorption) as a function of protein concentration in solution and processing conditions. 相似文献
995.
1-methylcyclopropene increases storability and shelf life in climacteric and nonclimacteric plums 总被引:2,自引:0,他引:2
Martínez-Romero D Dupille E Guillén F Valverde JM Serrano M Valero D 《Journal of agricultural and food chemistry》2003,51(16):4680-4686
The effect of 1-methylcyclopropene (1-MCP) at three different doses (0.25, 0.50, and 0.75 microL L(-1)) on the ripening processes of a climacteric, cv. Santa Rosa, and a suppressed climacteric type, cv. Golden Japan, plum was studied. For both cultivars, positive effects were observed in terms of inhibition of ethylene production and delays of the physical, chemical, and biochemical changes associated with ripening. 1-MCP-treated plums were firmer with lower weight loss, reduced degrees Brix/titratable acidity ratios, and lower color changes during cold storage and subsequent shelf life at 20 degrees C than controls. For most factors, the effectiveness of 1-MCP was dose-dependent in Santa Rosa but dose-independent for Golden Japan. 相似文献
996.
城市植被净化大气价值计量与评价——以西安市为例 总被引:17,自引:0,他引:17
对西安市植被净化大气物质量及价值测定结果表明 ,植被净化大气年总价值为 34 2 6 35 6亿元 ,占 1999年西安市国内生产总值的 6 % ,其中年固定CO2 和释放O2 的价值为 2 7 1830 9亿元 ,年吸收SO2 、HF和NOX3种污染物的价值为 1 82 896亿元 ,年滞尘价值为 1 82 5 11亿元 ,年灭菌价值为 3 4 2 6 4 0亿元。并通过MapInfo的叠加分析得出各行政区统计结果。 相似文献
997.
998.
Beltrán G Del Rio C Sánchez S Martínez L 《Journal of agricultural and food chemistry》2004,52(11):3434-3440
In this study was analyzed the effect of crop year and harvesting time on the fatty acid composition of cv. Picual virgin olive oil. The study was carried out during the fruit ripening period for three crop seasons. The mean fatty acid composition of Picual oils was determined. The oils contained palmitic acid (11.9%), oleic acid (79.3%), and linoleic acid (2.95%). The content of palmitic acid and saturated fatty acids decreased during fruit ripening while oleic and linoleic acids increased. The amount of stearic and linolenic acids decreased. The amount of saturated acids, palmitic and stearic, and the polyunsaturated acids linoleic and linolenic was dependent on the time of harvest, whereas the amount of oleic acid varied with the crop year. The differences observed between crop years for both palmitic and linoleic acid may be explained by the differences in the temperature during oil biosynthesis and by the amount of summer rainfall for oleic acid content. A significant relationship was observed between the MUFA/PUFA ratio and the oxidative stability measured by the Rancimat method. 相似文献
999.
García-González DL Barie N Rapp M Aparicio R 《Journal of agricultural and food chemistry》2004,52(25):7475-7479
A novel electronic nose based on solid-phase microextraction (SPME) coupled with a surface acoustic wave (SAW) sensor array has been used to analyze different quality virgin olive oils. A mathematical model was designed with 37 samples to distinguish lampante from the other virgin olive oils categories (extra-virgin and virgin), because lampante-virgin olive oils cannot be consumed without a previous refining process. The model, successfully validated with a test set of 16 samples, was able to classify 90% of the samples correctly. Misclassifications were explained by SPME-HRGC analyses and a second sensory evaluation. 相似文献
1000.
以 4个辣椒品种为材料 ,探讨飞船搭载对辣椒种子发芽力、植株生长特性、果实性状的影响。结果表明 :飞船搭载对辣椒种子的发芽率和发芽势有一定的影响 ,这种影响随材料而异 ;搭载种子平均初花期较对照提早 0 2~ 3 2d ,且株间变异增加 ,植株有矮化的趋势 ;第 1花序节位也呈降低态势 ,结果能力有所提高 ,但果实长度、直径和平均单果重呈下降趋势 相似文献