Expression analysis of endo‐1,4‐β‐glucanase genes during aril breakdown of harvested longan fruit

BACKGROUND: The aim of the present study was to investigate the expression profiles of three endo‐1,4‐β‐glucanase (EGase, EC 3.2.1.4) genes during aril breakdown of longan fruit stored at room temperature (25 °C), low temperature (10 °C) or on transferring fruit stored at 10 °C for 20 days to 25 °C. RESULTS: Three longan full‐length cDNAs, designated Dl‐EGase1, Dl‐EGase2 and Dl‐EGase3, were isolated and characterized. EGase activity in aril tissues of longan fruit increased with the appearance of aril breakdown symptoms, while RNA gel blot analysis revealed that the accumulations of three Dl‐EGase genes exhibited differential characteristics with the occurrence of aril breakdown. Dl‐EGase2 may be involved in the aril breakdown in longan fruit at the later stage of storage at room temperature. Conversely, expression of Dl‐EGase3 could be mainly involved in aril breakdown of fruit stored at 10 °C. In addition, Dl‐EGase3 and Dl‐Egase2 were related to the aril breakdown of fruit transferred from low temperature to room temperature. CONCLUSION: The results obtained in this study indicate that Dl‐EGase genes are involved in the aril breakdown of longan fruit and that considerable variation exists between expression patterns of individual members of the EGase gene family. Copyright © 2009 Society of Chemical Industry     

胡柚果醋生产菌种的筛选与鉴定

目的:筛选1株适合胡柚果醋生产的醋酸菌。方法:从自然发酵胡柚果醋中筛选产醋酸菌种,研究其酒精耐受性、酒精消耗速度、产醋酸速度;分别发酵生产胡柚果醋,对其进行感官分析,以Vitek-32型微生物分析系统对最适菌种进行鉴定。结果:筛选出3株性能较好的醋酸菌株,分别命名为HY05、HY19与HY36,其中HY05菌株性能最优,能够耐受14%的酒精浓度,起始酒精浓度为10%时酒精转化最快,产酸速度快,所生产的果醋色泽淡黄,质地澄清透亮,风味芳香怡人;根据形态观察与Vitek-32系统的分析结果,将其鉴定为醋杆菌属的巴氏醋杆菌(Acetobacter pasteurianus),命名为A.pasteurianus HY05。结论:A.pasteurianus HY05适宜胡柚果醋的生产。     

海南蒲桃果实原花青素的提取

以八成熟的海南蒲桃果实粉末为试材,采用正丁醇-盐酸法显色、测定提取液的吸光度,研究了八成熟海南蒲桃果实原花青素的提取工艺。经单因子实验及正交实验结果表明,以体积分数60%丙酮溶液(pH=3)为浸提液、料液比1∶9(g:mL)、温度60℃及时间2 h为最适工艺参数,经2次浸提原花青素的提取率为91.52%。八成熟的海南蒲桃果实原花青素含量5.70%,为充分成熟果实的127.23%。     

葡萄糖氧化酶在果汁保鲜中的应用

介绍了葡萄糖氧化酶作为果汁保鲜剂的作用机理及对果汁品质的影响，通过对在果汁中加入葡萄糖氧化酶进行抗氧化及抑制褐变实验，证明葡萄糖氧化酶可有效防止果汁氧化及抑制果汁褐变，对延长产品的保质期和保持果汁风味具有明显效果。同时葡萄糖氧化酶与增效剂联合使用，抗氧化和抑制褐变效果更好。     

抗氧化剂及其增效剂对荔枝、龙眼和芒果原果汁的抗氧化作用研究

以热带水果荔枝、龙眼、芒果为研究对象,选取叔丁基羟基茴香醚（BHA）、没食子酸丙酯（PG）、特丁基对苯二酚（TBHQ）、二丁基羟基甲苯（BHT）及茶多酚等作为抗氧化剂,柠檬酸、苹果酸、磷酸、葡萄糖酸钙、EDTA等作为抗氧化增效剂,进行单体和复合抗氧化剂抗氧化试验。结果表明：对龙眼果汁的抗氧化能力从大到小排列为：TBHQ〉BHT〉茶多酚〉PG〉BHA;各种增效剂均可明显增加TBHQ的抗氧化能力,对龙眼果汁的抗氧化能力从大到小排列为：TBHQ＋苹果酸＋EDTA〉TBHQ＋苹果酸〉TBHQ＋柠檬酸〉TBHQ＋EDTA〉TBHQ＋磷酸〉TBHQ＋葡萄糖酸钙;TBHQ加入柠檬酸及EDTA增效后对荔枝、芒果原果汁的抗氧化效果理想,VC保存率均达到85%以上。     

Development of probiotic fruit juice powders by spray-drying: A review

The use of spray-drying for the production of powdered fruit juices has been a common practice in recent years since it is a simple, economic, and advantageous technique. The current knowledge on the different spray-drying parameters, allowing the best conditions to obtain high-quality powders, is presented in this review. The incorporation of probiotic cultures into fruit juices can enhance the functional characteristics of fruit juices. The selection of these probiotics and their benefits to consumers’ health are briefly discussed. As maintaining the viability of probiotics is extremely important in the development of a probiotic functional product, the factors that influence and improve survival, in all pre- and post-spray-drying steps, are also detailed. Finally, a few studies on probiotic fruit juices obtained by spray-drying are cited. Industries should bet on their development and commercialization, since despite being challenging to develop, these are very innovative and attractive products meeting modern consumer demands.     

采前乙酰水杨酸与采后1-MCP处理对厚皮甜瓜冷藏品质及抗氧化能力的影响

以“玛瑙”厚皮甜瓜为试材,通过采前分别在幼果期（花后2 周）、膨大期（花后3 周）、网纹形成期（花后4 周）和采前2 d 4 个时期喷洒乙酰水杨酸和采后1-甲基环丙烯（1-methylcyclopropene,1-MCP）熏蒸,研究单独或复合处理对冷藏期间果实品质及抗氧化能力的影响。结果表明,采前乙酰水杨酸处理可有效抑制贮藏期间果实的质量损失率的增加,延缓果皮转黄,维持可溶性固形物和可滴定酸含量,提高总酚和类黄酮含量,提高抗氧化能力。1-MCP熏蒸能减少果实采后质量损失,维持硬度,增加抗坏血酸含量。复合处理在维持果实可溶性固形物和可滴定酸含量、提高总酚和类黄酮的含量方面表现出协同效应。由此表明,乙酰水杨酸和1-MCP处理对维持甜瓜果实采后品质的作用效果与抑制乙烯的产生有关,而果实抗氧化能力的提高则与促进苯丙烷代谢产物及抗坏血酸的积累相关。     

沙棘果油中维生素E的色质谱分析

本研究应用柱色谱预分离、气相色谱与质谱联用技术,在国内首次对野生植物沙棘果油中所含的维生素E类组份进行了系统的分析鉴定.除分析出了α、β、γ、δ——生育酚外,还用质谱碎片解析法推断出了四种未有报道的新组份,为沙棘果油在化妆品及医药方面的应用提供了可靠的依据.     

中国果蔬汁加工技术发展新趋势

简要介绍了中国果蔬汁加工新技术，如酶技术、膜技术、中温灌装技术等，并对这些技术的应用现状、存在问题及未来发展趋势进行了分析。     

涂膜保鲜剂中添加茶多酚对黄花梨贮藏品质的影响

探讨壳聚糖与天然抑菌抗氧化物质茶多酚对黄花梨进行涂膜保鲜的可行性。用茶多酚和壳聚糖混合液处理黄花梨,结合PE保鲜袋包装贮藏,测定贮藏过程中果实呼吸强度、多酚氧化酶(polyphenol oxidase,PPO)活性、VC含量、果实硬度及腐烂率等各项指标的变化。结果表明,壳聚糖联合茶多酚对黄花梨的保鲜效果优于单一保鲜剂,涂膜剂中添加茶多酚可明显抑制多酚氧化酶活性、延缓果实呼吸高峰出现的时间、降低黄花梨的烂果率,VC的保存率高于对照组。涂膜保鲜剂中添加茶多酚量为0.3%时保鲜效果最佳。壳聚糖中添加茶多酚能够明显延长黄花梨的保鲜期。