Control of anthracnose rot and quality deterioration in loquat fruit with methyl jasmonate

BACKGROUND: Loquat (Eriobotrya japonica Lindl.) fruit has a short shelf‐life, mainly due to fungal decay. Current control of postharvest disease of the fruit is mainly dependent on fungicides. However, because of the increasing consumer concern over food safety, there is an urgent need to search for effective alternatives to control disease. The objective of this work was to determine the efficacy of methyl jasmonate (MeJA) in controlling anthracnose rot caused by Colletotrichum acutatum and maintaining quality of loquat fruit. RESULTS: Loquat fruit were treated with 10 µmol L^?1 MeJA and wound inoculated with C. acutatum spore suspension of 1.0 × 10⁵ spores mL^?1 24 h after treatment, and then stored at 20 °C for 6 days. The percentage of infected wounds showing decay symptom was reduced from 54.4% to 16.7% and the lesion diameter was reduced from 7.26 mm to 4.00 mm by MeJA treatment on the 4th day after inoculation. MeJA treatment induced higher activities of two defense‐related enzymes—chitinase and β‐1,3‐glucanase—during 6 days storage. Meanwhile, the treatment inhibited increases in fruit firmness and internal browning index, and maintained higher extractable juice rate and total soluble solids and titratable acidity contents, thereby delaying the development of flesh leatheriness. CONCLUSION: MeJA treatment effectively inhibited anthracnose rot and maintained quality in loquat fruit. Inhibition of the disease was mainly because of resistance induced in loquat fruit by MeJA. A postharvest application of MeJA could be an alternative to chemical fungicides for control of postharvest disease in loquat fruit. Copyright © 2008 Society of Chemical Industry     

不同品种枇杷果实采后低温贮藏品质研究

目的 明确不同品种枇杷果实采后低温贮藏期间腐烂和品质变化的差异, 为枇杷果实贮运技术的开发提供理论依据。方法 研究了“洛阳青”、“宁海白”和“大红袍”3个品种枇杷果实5 ℃贮藏35 d期间失重率、腐烂指数、果皮和果肉颜色变化、可溶性固形物、维生素C、类胡萝卜素和总酚含量的变化。结果 “洛阳青”和“大红袍”枇杷果实采后可溶性固形物、维生素C含量和L值下降, 失重率和腐烂指数上升, 果实贮藏品质发生劣变。枇杷果实贮藏前期果皮和果肉b值升高, 类胡萝卜素和总酚含量增加。但随着贮藏时间的延长, 果实中类胡萝卜素和总酚含量逐渐下降。结论 与“宁海白”枇杷果实相比, “洛阳青”和“大红袍”枇杷果实采后5 ℃贮藏期间易发生腐烂, 品质劣变严重, 耐贮性低。     

枇杷酒苹果酸乳酸发酵耐硫优良菌株的筛选

以菌体增长倍数和菌量级别为指标,以Lac101和酒明串珠菌6066为对照菌,考察了从枇杷酒中分离的12株乳酸菌对SO2、乙醇、酸、温度的耐受能力和苹果酸乳酸发酵活力。结果表明,杆菌中的R23与球菌中的R33、R35综合能力最强,可在SO2和乙醇浓度分别为120 mg/L和13%(v/v),pH3.0时维持生长,在18℃下菌量可达109CFU/mL,3菌株的苹果酸乳酸发酵活力均在100u以上,综合性能均优于对照菌Lac101和6066。R23与R33、R35是3株优良的枇杷酒苹果酸乳酸发酵菌株。     

Effect of 1‐methylcyclopropene on anthracnose rot caused by Colletotrichum acutatum and disease resistance in loquat fruit

BACKGOUND: Loquat (Eriobotrya japonica Lindl.) fruit are susceptible to fungal decay during postharvest storage at ambient temperature. The control of postharvest diseases of loquat is based primarily on the use of synthetic fungicides. To look for an alternative method for disease control, we investigated the effect of 1‐methylcyclopropene (1‐MCP) on controlling anthracnose rot caused by Colletotrichum acutatum of loquat fruit. RESULTS: 1‐MCP treatment significantly reduced decay incidence of loquat fruit. The treatment markedly inhibited accumulation of superoxide radicals and hydrogen peroxide and maintained higher superoxide dismutase, catalase and ascorbate peroxidase. Meanwhile, 1‐MCP treatment induced higher activities of two defense‐related enzymes—chitinase and β‐1,3‐glucanase—during 6 days' storage. Furthermore, the treatment inhibited increases in fruit firmness and internal browning index, and maintained higher extractable juice rate, total soluble solids and titratable acidity contents, thereby delaying the development of senescence. CONCLUSION: 1‐MCP was effective in reducing decay and might have enhanced the disease resistance in loquat fruit by increasing chitinase and β‐1,3‐glucanase, and maintained natural resistance by delaying senescence development. Copyright © 2010 Society of Chemical Industry     

Effect of methyl jasmonate on quality and antioxidant activity of postharvest loquat fruit

BACKGOUND: Loquat fruit is rich in natural antioxidants and has shown a remarkably high antioxidant activity. To search for an effective method for maintaining or even improving antioxidant activity during postharvest storage, we investigated the effect of 10 µmol L^?1 methyl jasmonate (MeJA) treatment on levels of major individual sugars and organic acids, total phenolics, total carotenoids, total flavonoids and antioxidant activity in loquat fruit during storage at 1 °C for 35 days. RESULTS: The MeJA‐treated fruit exhibited significantly lower levels of respiration rate, ethylene production, phenylalanine ammonia‐lyase and polyphenol oxidase activities, and higher levels of sugars, organic acids, total phenolics and total flavonoids than control fruit. Meanwhile, the treatment also maintained significantly higher antioxidant activity as measured by the scavenging capacity against 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), superoxide and hydroxyl radicals, and by the reducing power test compared to the control. There was a significant positive linear relationship between total phenolic content and DPPH radical scavenging activity. CONCLUSION: MeJA treatment can improve the quality and functional properties of harvested loquat fruit by maintaining a higher level of antioxidants and enhancing antioxidant activity. Copyright © 2009 Society of Chemical Industry     

HACCP在绿色食品枇杷汁饮料加工中的应用研究

根据HACCP原理,通过对绿色食品枇杷汁饮料加工工艺流程进行危害分析,确定了原料和灌装瓶、盖接收,加热配料,热灌装三个关键控制点,提出了关键控制点的关键限值、监控方法和纠正措施,进行有效地控制从而保证产品质量。     

超声波辅助提取枇杷叶中的熊果酸的工艺研究

为了充分利用枇杷中的熊果酸,以枇杷叶为原料,以熊果酸提取率为指标,采用超声波辅助提取了枇杷叶中的熊果酸。分别研究了乙醇浓度、料液比、超声波时间和超声波温度对熊果酸提取的影响,通过正交实验优化了提取工艺。结果表明,熊果酸提取的最佳工艺条件是：乙醇浓度为85％、料液比为1：12、超声波时间为25min、超声波温度为45℃,在最佳条件下,熊果酸提取率可达1．131％。     

可编程控制器在水库枇杷园区生态保护中的应用

本设计将采用可编程控制器在枇杷园区实施灌溉施肥自动控制,灌溉施肥方式为分组轮灌。灌水量和施肥量的控制要求采用自动控制系统,有控制器自动定时,按序开关各灌溉区的供水电磁阀。     

不同保鲜纸对枇杷货架期品质及生理特性的影响

为探究不同保鲜纸对采后枇杷货架品质及生理特性的影响。以"大五星"枇杷为试验材料,用不同处理的保鲜纸（500 mg·L-1纳他霉素、500 mg·L-1 ε-聚赖氨酸、500 mg·L-1二氧化氯）放入装有枇杷的保鲜箱内,在（20±0.5）℃货架条件下贮放,研究其枇杷在货架期品质及生理特性的变化。结果表明:与对照组（CK）比较,不同保鲜纸均能够延缓枇杷果实的腐烂率及失重率上升,抑制枇杷鲜果的V_C含量、可滴定酸含量和可溶性固形物含量的下降,降低枇杷鲜果呼吸强度及乙烯生成速率,较好地抑制过多酚氧化酶（PPO）活性和氧化物酶（POD）活性。其中,在货架期12 d时,CK组、纳他霉素、ε-聚赖氨酸、二氧化氯的枇杷腐烂率分别为27.45%、22.56%、18.76%、14.62%。采后用二氧化氯型保鲜纸处理枇杷的保鲜效果最好,能够推迟枇杷的衰老进程,保持枇杷良好的货架期品质。     

枇杷花叶主要功能成分分步提取及其压片糖果工艺配方优化研究

目的:寻求合适工艺提取枇杷花叶中的总三萜酸、总黄酮、多糖,并研发枇杷花叶提取物压片糖果制备的最优配方工艺。方法:枇杷花、叶洗净烘干,用搅拌机粉碎、过筛,采用分步法提取花叶(1:1,g/g)中总三萜酸、总黄酮和多糖,以单因素实验法确定其合适的提取工艺参数;在单因素实验基础上,采用正交实验(L;(3;))优化枇杷花叶提取物压片糖果的工艺配方。结果:总三萜酸提取的合适工艺为100%乙醇、料液比1:40(g/mL)、提取温度50℃、提取时间2 h,粗提物得率为1.6%;总黄酮提取的合适工艺为60%乙醇、料液比1:20(g/mL)、提取温度50℃、提取时间2 h,粗提物得率为17.9%;多糖水提的合适工艺为料液比1:15(g/mL)、提取温度80℃、提取时间2 h,粗提物得率为1.0%。枇杷花叶提取物压片糖果的最优配方为:枇杷花叶提取物(总三萜酸:总黄酮:多糖=2:18:1,g/g/g)0.2 g、填充剂(微晶纤维素:预胶化淀粉=1:1,g/g)7.5 g、调味剂(木糖醇:柠檬酸=50:1,g/g)5.0 g、硬脂酸镁1%。结论:文章所涉及的提取和制备方法具有工艺简单、可行性好等优点,可适用于工业化生产,所制得的枇杷花叶提取物压片糖果口感酸甜适中、粉感不明显,外观光滑美观,感官质量符合国家标准要求。