不同预冷方式对“储良”龙眼贮藏品质的影响

为掌握龙眼不同预冷方式对低温贮藏品质的影响,以海南省龙眼品种"储良"果实为材料,分别进行冰水预冷、冷库预冷和阴凉通风处预冷处理,进行冷库6℃±1℃贮藏17 d,分析对比不同预冷方式对龙眼贮藏后的质量影响。通过分析在贮藏期间好果率、可溶性固形物、维生素C、还原糖、呼吸强度、果皮相对电导率和果肉丙二醛8个指标在贮藏过程中变化规律,确定最佳预冷方式。结果表明:不同预冷方式差异显著(p0.05),冰水预冷方式效果最好。冰水预冷后贮藏的龙眼好果率为91.2%,龙眼果肉SSC、维生素C和还原糖等营养物质含量变化小,且果肉褐变度低,明显降低龙眼的呼吸强度、细胞膜透性和丙二醛含量,为龙眼预冷后实现远距离冷链运输提供参考。     

不同保藏方式对龙眼贮藏过程中感官与理化品质的影响

研究不同保藏方式对龙眼贮藏过程中感官与理化品质的影响。分别对龙眼进行抽真空包装和充氮气包装,设置常温和低温(4℃)两种贮藏条件,通过测定贮藏过程中龙眼的感官品质和理化指标(可滴定酸度、还原糖含量、水分含量、维生素C含量)的变化来比较不同保藏方式下龙眼的品质变化。结果表明:真空包装和充氮气包装均可延缓贮藏过程中龙眼感官品质的劣变;低温贮藏能有效抑制贮藏过程中龙眼各理化指标的褪变,延长其货架期; 4℃、真空保藏方式下贮藏的龙眼的总体品质最优,展现出优良的感官和理化指标。     

不同温度、1-MCP浓度和薄膜包装对青脆李耐贮性的影响

比较了不同温度(4、10℃和常温)、不同浓度1-MCP(0.5μL/L、0.75μL/L和1.0μL/L)和不同薄膜(PE膜、PVC膜、微孔薄膜)包装青脆李贮藏期间果实品质的变化。结果表明:4℃条件下青脆李果实贮藏期从常温下的3-5d延长至16d左右,延长贮藏时间约10d,其中好果率大于90%,并有效保持青脆李果实硬度,抑制SSC、TA、可溶性糖含量的降低;0.75μL/L 1-MCP处理后的青脆李于4℃条件下贮藏期可达到25d,好果率大于90%,有利于抑制果实硬度和SSC含量的下降,有效维持青脆李果实糖酸含量;PE膜包装有利于抑制果实硬度、SSC的下降,微孔膜有利于抑制TA含量的下降,PVC膜能保持果实较高可溶性糖含量。4℃、0.75μL/L 1-MCP和薄膜包装分别为最适合于青脆李贮藏保鲜的单因素条件。     

鲜食糯玉米贮藏过程中可溶性糖含量变化的研究

以垦糯1号为研究对象,利用高效液相色谱法测定不同贮藏温度(5℃、15℃、25℃)下的鲜食玉米在48h内可溶性糖含量的变化。结果表明,可溶性糖含量随着温度的升高、贮藏时间的延长呈下降趋势,且下降主要是由蔗糖引起的(5℃下降97%、15℃下降98%、25℃下降94%);低温可以延缓可溶性糖含量的下降,与15℃和25℃相比,5℃条件下可溶性糖含量降低幅度最小(5℃下降34%、15℃下降49%、25℃下降55%),是鲜食玉米贮藏的理想温度。     

贮藏温度对湖南本地青椒采后理化品质的影响

目的研究贮藏温度对湖南本地青椒采后理化品质的影响,确定不同温度下青椒采后品质变化规律。方法考察不同温度(8℃和25℃)在贮藏20 d期间青椒理化品质变化,包括失重率、硬度、叶绿素含量、可溶性糖含量、有机酸含量、总酚含量及抗氧化活性(DPPH·清除能力、ABTS~+能力、FRAP能力)变化规律。结果同25℃相比, 8℃贮藏温度下青椒的理化品质保持更好。8℃处理组的青椒在贮藏期间失重率小,硬度较高,叶绿素、可溶性糖和有机酸含量变化幅度小,抗氧化活性较高。结论 8℃低温贮藏更有利于青椒采后理化品质的保持,延长其货架期。     

油豆角冰温贮藏对淀粉与蛋白质降解速度的影响

以"将军"油豆角为试材,分析了不同温度贮藏过程中油豆角淀粉、可溶性糖、可溶性蛋白和游高氨基酸的变化。结果表明:0℃冰温贮藏的油豆角淀粉和可溶性蛋白降解的速度最慢,8℃次之,25℃最快;不同温度贮藏期间可溶性糖含量有差异,25℃贮藏油豆角的果糖、葡萄糖、蔗糖和总糖含量迅速降低,8℃贮藏油豆角可溶性糖消耗速度大于冰温贮藏,其果糖、葡萄糖、蔗糖和总糖含量低于冰温贮藏的油豆角;冰温贮藏末期油豆角游离氨基酸总量及必需氨基酸含量均高于8℃。     

贮前光照处理对伽师瓜贮藏品质及部分防御酶活性影响

以伽师瓜为试材,研究了采后贮前经4500 lux光照处理对25℃下贮藏的甜瓜果实品质及部分酶活性的影响。伽师瓜在贮藏前处理阶段经光照强度4500 lux,贮藏温度25℃保存,后期贮藏阶段经0 lux,7℃保存,测定整个贮藏期间果实硬度及失重率、可溶性固形物、果皮色素含量、还原糖含量,以及过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)活性。结果表明:伽师瓜经光照,软化加快,并显著地提高了果实失重率(p 0.05);经过49 d贮藏,光照果实可溶性固形物含量仅下降了25.13%,还原糖含量上升了65.0%;光照促使伽师瓜果皮色素含量的积累,光照与避光两种色素含量变化均存在显著差异(p 0.05);同时,光照CAT、POD、PPO酶活性均高于避光处理,且果皮酶活性均显著大于果肉(p 0.05)。     

不同贮藏条件下油茶籽品质及生理活性

为了延长油茶籽的加工期限,将含水量为6%、13%的油茶籽分别贮藏在25℃、室温、4℃,相对湿度(RH)50%～65%条件下,观察贮藏期间品质及生理生化变化。结果表明：所有实验贮藏方法,油茶籽贮藏90d后均出现一定程度的劣变现象,贮藏品质下降。对不同处理贮藏效果的综合评价,最好的贮藏条件为温度4℃、油茶籽含水量6%,能明显抑制呼吸强度和脂肪酶活性,保持较高蛋白质、脂肪、糖等内含物质的含量,阻止油茶籽品质的劣变;其次为温度4℃、含水量13%,最差的为温度25℃、含水量13%。低温和低水分含量可有效提高油茶籽的贮藏品质。     

贮藏温度对雪莲果块根品质的影响

本文研究了不同贮藏温度对雪莲果块根中总糖、低聚果糖、蛋白质可溶性固形物含量及果实硬度的影响,同时分析了多酚氧化酶、过氧化氢酶在不同贮藏温度下随时间的变化关系。结果显示,在贮藏过程中,贮藏温度越高,总糖、蛋白质含量降幅越大,降速越快,尤其是在前7d,而0℃和4℃的贮藏效果则相对较好,综合硬度和低聚果糖含量来考虑,4℃下贮藏效果较好。多酚氧化酶和过氧化物酶在4个贮藏温度下均呈现先升后降的趋势,且温度越高,酶活性峰值越早出现。     

低温贮藏对晚熟龙眼“立冬本”果实采后生理和品质的影响

研究了龙眼"立冬本"果实在采后(25±0.5)℃和(3±0.5)℃温度下的呼吸强度、细胞膜透性和品质的变化。结果表明:龙眼果实属于非呼吸跃变型果实;在(25±0.5)℃下贮藏4天,果实呼吸强度下降,之后明显上升;果实采后果皮细胞膜透性快速增加,果实易失重、衰老、腐烂和果皮褐变,贮藏后期果肉自溶;果肉可滴定酸和维生素C含量快速下降,总糖和蔗糖含量下降,还原糖含量先升后降,可溶性固形物含量在贮藏前期下降而后期上升,可溶性固形物和可滴定酸比值先升后降;贮藏后期果肉可滴定酸含量增加。而(3±0.5)℃低温贮藏可显著降低果实呼吸强度,抑制病原菌生长,延缓果实衰老和果皮细胞膜透性增加,延迟果皮褐变,减少果实失重和果肉营养成分变化,抑制果肉自溶,保持果实较高的品质,延长果实贮藏期。     

不同贮藏温度条件下菜用大豆蔗糖代谢与相关酶活性变化

以‘新大粒1号’菜用大豆为试材,研究不同贮藏温度（1、5、10、20 ℃）条件下菜用大豆蔗糖代谢及相关酶活性的变化情况。结果表明,贮藏期间菜用大豆蔗糖、果糖及葡萄糖含量均呈整体下降趋势,1 ℃有效控制了蔗糖降解;酸性转化酶（AI）活性在第1天达到峰值后逐渐下降,不受贮藏温度影响;20 ℃条件下中性转化酶（NI）活性持续增加,至第4天达到最大值,其他温度组变化差异不显著（P＞0.05）;蔗糖合成酶（SS）活性略有降低后快速升高,至第4天达到峰值后逐渐下降;蔗糖磷酸合成酶（SPS）活性呈整体下降趋势,与蔗糖含量呈极显著正相关（P＜0.01）,与果糖含量呈显著正相关（P＜0.05）,其他酶活性与糖含量之间均无显著相关性（P＞0.05）。这表明SPS可能与‘新大粒1号’菜用大豆中蔗糖降解密切相关。     

采后黄冠梨果实糖代谢及相关酶活性变化规律

以黄冠梨为试材,研究采后梨果实糖代谢及相关酶活性的变化规律。果实采后即贮于温度0℃、相对湿度85%～95% 的冷库中,分别测定贮藏过程(0～240d)中果实中葡萄糖、蔗糖、总可溶性固形物(TSS)和可滴定酸(TA)的含量以及酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性。结果表明：在采后贮藏期间,黄冠梨果实中葡萄糖含量与AI、NI 活性均呈先升后降的趋势,且AI 活性出现明显高峰,而蔗糖含量与SS、SPS 活性均逐渐降低。TA 和TSS 含量是果实风味的重要指标,随着贮藏期的延长,TA 含量逐渐下降,而TSS 含量呈升- 降- 升的趋势。果实中蔗糖代谢参与酶的净合成活性与果实中蔗糖的积累密切相关,在采后贮藏期间其活性逐渐降低。     

1-MCP处理对不同期采收的阿克苏富士苹果在采后贮藏期糖代谢的影响

以阿克苏富士苹果为试材,通过测定在贮藏过程中(0~150d),果实蔗糖、葡萄糖、果糖和山梨醇含量,以及蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS-S、SS-C)、酸性转化酶(AI)、中性转化酶(NI)和山梨醇脱氢酶(SDH)的活性,研究采后苹果果实糖代谢及相关酶活性的变化规律并分析了1-MCP处理对它们的影响。结果表明:在采后贮藏期间1-MCP处理在一定程度上抑制了贮藏过程中富士苹果果实蔗糖、葡萄糖、果糖和山梨醇含量的增加,且对不同采收期果实酶活性的影响效果不同,果实中蔗糖、山梨醇含量以及SDH活性呈下降趋势,果糖含量、葡萄糖含量、与SPS、SS-S活性呈先下降后上升趋势,AI与NI在贮藏过程中出现明显峰值,且1-MCP处理可以显著提高这一峰值。     

Characterisation of genes encoding key enzymes involved in sugar metabolism of apple fruit in controlled atmosphere storage

Sugars are essential contributors to fruit flavour. Controlled atmosphere (CA) storage has been proved to be beneficial for maintaining harvested fruit quality. To explore regulatory mechanism of sugar metabolism in fruit stored in CA condition, we cloned several genes, encoding key enzymes, involved in sugar metabolism in apple fruit, and analyzed sugar contents, along with gene expression and enzyme activities in fruits stored in air and CA. The results indicated that CA could maintain higher contents of sugars, including sucrose, fructose and glucose. Expression levels of key genes, such as sucrose synthase (SS), sucrose phosphate synthase (SPS), fructokinase (FK) and hexokinase (HK), were shown to be correlated with the corresponding enzyme activities. We found that activities of neutral invertase (NI), vacuolar invertase (VI), FK and HK were inhibited, but SPS activity was promoted in apple fruit stored in CA, suggesting that CA storage could enhance sucrose synthesis and delay hydrolysis of sucrose and hexose. These findings provided molecular evidence to explain why higher sugar levels in harvested fruit are maintained under CA storage.     

Sugar metabolism and involvement of enzymes in sugarcane (Saccharum officinarum L.) stems during storage

Sugarcane (Saccharum officinarum L. cv. Badila) was harvested at the mature stage and stored at 2, 10, and 20 °C for 30, 90, and 120 days, respectively. Metabolic changes in the contents of sucrose and reducing sugar in relation to the activities of soluble acid invertase (SAI), neutral invertase (NI) and sucrose-phosphate synthase (SPS), in sugarcane juice, were studied. Extractable juice, sucrose and vitamin C declined significantly with increasing storage temperatures, while respiration rate increased. There was a rapid increase in titratable acidity during storage, with a more rapid rate at higher temperatures. A sharp increase in reducing sugar was observed within 20 days at 20 °C and 70 days at 10 °C, followed by a rapid decrease. Both SAI and NI activities showed a sharp increase within 15 days at 20 °C, followed by a rapid decrease, while a moderate increase occurred within 40–60 days at 10 °C. Slight increases were observed in SPS activity within 20 days at 20 °C and 50 days at 10 °C. Enzyme activities remained steady or underwent a small change in canes stored at 2 °C. Enzyme activities were significantly correlated with reducing sugar content.     

套袋对清见橘橙果实蔗糖代谢的影响

研究6 种果袋对清见橘橙果实可溶性糖含量及蔗糖代谢关键酶活性的影响。结果表明：不同果袋对清见橘橙果实可溶性糖含量的影响不同,单层果袋显著提高了果实的可溶性糖含量。果实成熟时,套白色单层无纺布袋的果实蔗糖含量最高,套黄色单层袋和白色单层袋的果实果糖含量均最高,套白色单层袋的果实葡萄糖含量最高。单层果袋提高了果实中性转化酶（NI）、蔗糖合酶（SS）和蔗糖磷酸合酶（SPS）的活性,以无纺布袋最为明显,而双层果袋对NI、SS、SPS活性的影响在多数测定点差异不显著。酸性转化酶（AI）活性随着果实的成熟而降低,套袋对AI活性的影响不显著。综上可知,单层果袋通过提高NI、SS、SPS的活性来提高糖含量,因此清见橘橙宜选择具有一定透光率且色泽浅的单层果袋。     

CHANGES IN SUGARS AND LYSINE IN BABY FOODS DURING STORAGE

The effect of storage on sugar content (fructose, glucose, sucrose) and free lysine in vegetable, meat, fish and fruit baby foods for a period of two years and at temperatures of 5, 15 and 25C were studied. The results showed that under these storage conditions a decrease occurred in fructose, glucose and sucrose for vegetable, meat and fish foods. A drop in sucrose was found in the fruit sample, together with an increase in fructose and glucose. The increase of reducing sugars in this sample is attributed to the hydrolysis of sucrose, an effect which is favorable because of storage temperature. A drop in free lysine was found for the four types of samples; this decrease was dependent on storage temperature but mainly on the time of storage. After one year, the levels of lysine were decreased by half or more at all temperatures. Although infants can get lysine from other sources such as milk and cereals, the lysine loss can be important leading to negative nutritional consequences if infants mainly eat baby foods stored at least for one year. The loss of reducing sugars and of lysine showed that during storage of these products a Maillard browning reaction between reducing sugar and lysine occurred.     

贮藏温度对哈密瓜蔗糖代谢途径中14种酶活性的影响

为了系统研究哈密瓜在不同贮藏温度条件下的蔗糖积累和呼吸代谢情况,在不同贮藏温度（0、5、10、 15、20、25、30、35、40、45 ℃）测定哈密瓜外果皮、内果皮、外果肉、中果肉、内果肉5 个部位蔗糖、乳酸、呼 吸代谢途径中14 种酶的基因表达活性及其变化情况。结果表明：哈密瓜果实5 个部位中蔗糖转化酶和乳酸脱氢酶活 性最高,其活性大小依次为：内果皮＞外果肉＞外果皮＞中果肉＞内果肉;哈密瓜在5 ℃贮藏时,包括蔗糖转化酶 和乳酸脱氢酶的14 种酶的活性均处于最低水平,可见5 ℃可有效地控制蔗糖代谢,是哈密瓜的最适贮藏温度。     

Soluble Sugar Content and Metabolism as Related to the Heat-Induced Chilling Tolerance of Loquat Fruit During Cold Storage

The effects of high-temperature, short-time hot air treatment (45 °C for 3 h) on soluble sugar metabolism and chilling tolerance in loquat fruit stored at 5 °C for 5 weeks were investigated. Heat treatment significantly reduced chilling severity, as evidenced by lower firmness and internal browning and higher levels of extractable juice. Meanwhile, this treatment accelerated the activities of acid invertase, neutral invertase, sucrose phosphate synthase and sucrose synthase during storage. However, sucrose degradation was predominant, which caused lower levels of sucrose and higher levels of glucose and fructose in the heat-treated group. In addition, the ascorbate acid content and the activities of ascorbate peroxidase and glutathione reductase in the heat-treated fruit were much higher than those in control fruit, resulting in lower levels of hydrogen peroxide (H₂O₂) and malondialdehyde and decreased membrane permeability as well as a higher unsaturated/saturated fatty acid ratio at the end of storage. Our results suggest that the increased levels of reducing sugars, especially those of glucose, may induce the ascorbate–glutathione cycle activity to scavenge for H₂O₂, whose content relates to the heat-induced chilling tolerance of loquat fruit.     

The Effects of Harvest Maturity on Storage Quality and Sucrose-Metabolizing Enzymes During Banana Ripening

Mature green “Baxi” banana (Musa spp. AAA Group, Cavendish) fruits were harvested at 60% and 80% maturity stages. In order to evaluate the effects of harvesting at different maturity stages on storage quality and changes in sucrose-metabolizing enzymes, fruit firmness, disease index, contents of starch, and total soluble sugars were determined, and enzyme activities associated with sucrose metabolism was investigated under natural and accelerated (treated with ethylene) ripening conditions. In fruit treated with ethylene, changes in flesh firmness, total sugar content, starch content, disease index, and activity of sucrose phosphate synthase (SPS), sucrose synthase (SS), acid invertase (AI), and neutral invertase (NI) were accelerated dramatically compared with untreated fruit with both 60% and 80% maturity. When fruit ripened under natural conditions, the changes in firmness, disease index, starch content, total sugar content, SPS activity, SS, AI, and NI activity in fruit with 80% maturity were significantly faster than those in fruit with 60% maturity. On the contrary, when fruit ripened under accelerated conditions, no significant differences in firmness, sugar, starch, disease index, SPS, SS, AI, and NI were observed between fruit harvested at 60% or 80% maturity. It is suggested that storage quality and sucrose-metabolizing enzymes of banana fruit stored under natural conditions are related to harvest maturity stage; storage quality of fruit with lower harvest maturity is better than fruit with higher maturity. However, when fruit ripening is accelerated by ethylene, the harvest maturity stage has no influence on storage quality and changes in sucrose-metabolizing enzymes.