壳聚糖姜精油复合保鲜剂对甜椒贮藏品质的影响

为探究有效延长甜椒货架期的方法,以壳聚糖姜精油复合保鲜剂对甜椒涂膜,在8℃下贮藏35 d,分析其贮藏期间的失重率、过氧化物酶活性、叶绿素、VC等营养特性及理化指标的变化。结果表明,体积分数为0. 1%的姜精油壳聚糖复合保鲜剂对于甜椒的保鲜效果最佳,降低了样品贮藏期的失重率,诱导植物体内防御酶POD的产生,减少了VC的损失,保持了叶绿素的含量,抑制了细菌的繁殖。并且,贮藏期间涂膜处理后的甜椒样品电导率和丙二醛含量均有所增加,但仍远低于对照组。该结论为壳聚糖复合涂膜的应用提供了方向,为今后甜椒保鲜提供理论参考。     

1-MCP结合壳聚糖处理延缓芒果果实后熟与衰老的研究

以未处理芒果(Mangifera indica L.)果实为对照,研究了1.5μL/L 1-甲基环丙烯(1-MCP)、2.0%壳聚糖及其联合处理对芒果果实采后贮藏期间呼吸强度、失重率、硬度、丙二醛含量、可溶性固形物质量分数和过氧化物酶活性的影响。结果表明,与对照组相比,各处理组均能有效抑制芒果呼吸强度、失重率、丙二醛含量、可溶性固形物质量分数和过氧化物酶活性的上升,并延缓果实硬度的下降。其中,1.5μL/L 1-MCP和2.0%壳聚糖涂膜联合处理对保持芒果的贮藏品质更显著。     

壳聚糖涂膜与牛至精油复配对鲜切菠萝的 保鲜作用

目的研究壳聚糖涂膜及与牛至精油复配对鲜切菠萝的保鲜的影响。方法在低温环境中,按照0.1%、0.3%和0.5%不同浓度的牛至精油与壳聚糖复配,并分别以水、壳聚糖涂膜处理为对照,分析不同处理方式对鲜切菠萝硬度、Vc含量、过氧化物酶(POD)、多酚氧化酶(PPO)、过氧化氢酶(CAT)和脂氧合酶(LOX)活性的影响。结果壳聚糖涂膜与0.5%的牛至精油复配后可减缓组织软化;与0.1%牛至精油复配可以维持Vc含量的缓慢降低。在不同处理组中,当含有0.3%和0.5%牛至精油时,鲜切菠萝的POD和CAT活性则呈下降趋势,而其他处理组则显著升高;当含有壳聚糖处理组时,其PPO和LOX活性则低于对照组。结论壳聚糖与牛至精油复配涂膜会在减缓鲜切菠萝营养损失的情况下延长其货架期。     

壳聚糖涂膜保鲜对黄秋葵果实常温贮藏品质及生理的影响

为探讨壳聚糖对黄秋葵果实常温下的保鲜效果,筛选适宜黄秋葵的壳聚糖处理浓度,并探究壳聚糖对黄秋葵品质及生理的影响,以台湾五福黄秋葵为实验材料,采后用0、0.5%、1.0%、1.5%浓度的壳聚糖处理后,置于常温(20±1)℃下贮藏,从品质和生理角度探讨壳聚糖对黄秋葵果实的常温保鲜效果。结果表明:壳聚糖涂膜能够对黄秋葵采后保鲜起到明显效果,但不同浓度壳聚糖处理效果不同,其中1.0%壳聚糖涂膜组对黄秋葵的贮藏品质保持最好。能够显著地(p0.05)降低黄秋葵果实常温贮藏下的呼吸强度,推迟呼吸高峰的出现,延缓叶绿素含量的下降,抑制丙二醛含量和相对电导率的上升,并维持较高的过氧化物酶、过氧化氢酶活性等。     

海带多糖复合涂膜对辣椒保鲜效果的研究

采用不同配比的海带多糖复合溶液对辣椒进行涂膜保鲜,研究了海带多糖复合涂膜对室温贮藏期辣椒的过氧化物酶、超氧化物歧化酶、叶绿素、VC、失重率、腐烂率的影响。结果表明:海带多糖复合膜可显著缓解辣椒的失重和腐烂率,降低了过氧化物酶和超氧化物歧化酶活性,并保持有较高的叶绿素和VC含量。配方为2%海带多糖+0.4%壳聚糖+0.2%魔芋葡甘聚糖,对辣椒的保鲜效果最好。     

含茶多酚的壳聚糖涂膜对四季豆贮藏品质和 生理生化特性的影响

目的研究壳聚糖联合茶多酚对四季豆涂膜保鲜的可行性。方法以四季豆为实验材料,采用壳聚糖涂膜(浓度为1.5%)、壳聚糖联合茶多酚复合涂膜(1.5%壳聚糖中添加150 mg/kg茶多酚)2种保鲜方式,研究茶多酚对四季豆贮藏品质和生理生化特性的影响。结果茶多酚联合壳聚糖涂膜的四季豆在贮藏期内叶绿素、维生素C、水分含量的下降速率和纤维素含量的上升速率均低于壳聚糖涂膜组,贮藏品质较好。茶多酚联合壳聚糖涂膜的四季豆体内的过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活力低于壳聚糖涂膜组,但二者均高于未处理组。结论涂膜处理有利于四季豆的贮藏,涂膜剂中加入茶多酚后保鲜效果更好,和壳聚糖涂膜相比可将四季豆贮藏期延长10 d,和不涂膜组相比可延长20d。     

壳聚糖/纳米TiO_2复合涂膜对鲜切荸荠保鲜作用研究

采用壳聚糖/纳米TiO_2作为复合涂膜剂,低温(0～4℃)条件下对鲜切荸荠进行涂膜处理,测定鲜切荸荠贮藏过程中失重率、V_C含量、褐变度(BD)、过氧化物酶(POD)活性等的变化。结果表明:壳聚糖/纳米TiO_2复合涂膜可有效降低果实的水分、V_C等成分的损失,延缓荸荠褐变的发生,从而延长鲜切荸荠的货价保藏期。     

壳聚糖涂膜处理对常温贮藏红江橙保鲜效果的影响

主要研究壳聚糖涂膜处理时常温贮藏红江橙保鲜效果的影响.结果表明:0.5%、1.0%壳聚糖涂膜处理能有效抑制呼吸强度、降低PPO酶的活性、维持CAT较高的活性,明显抑制果皮电导率的升高,有效抑制果实VC和可溶性固形物含量的降低,保持果实的硬度,显著抑制果实失水和腐烂,从而有效延缓红江橙果实的成熟和衰老,延长贮藏期.1.0%壳聚糖涂膜处理效果最好,而1.5%壳聚糖涂膜处理由于膜层过厚皲裂,不能起到应有的作用.     

壳聚糖涂膜处理对翠冠梨果实常温货架期色泽和贮藏品质的影响

以翠冠梨果实为试验材料,研究1.0%、1.5%和2.0%壳聚糖涂膜处理对翠冠梨果实常温货架期色泽和贮藏品质的影响。试验结果表明:壳聚糖涂膜处理能延缓果实色泽变化,抑制果实果皮色泽向黄褐色转变、延缓果皮叶绿素含量的降低和类胡萝卜素的积累。与对照组(CK)果实相比,壳聚糖涂膜果实腐烂率、失重率、呼吸强度均降低,能够使果实硬度和营养品质维持在较高水平。说明壳聚糖涂膜处理能够作为翠冠梨果实的保鲜技术以提高成熟翠冠梨采后的贮藏品质,其中1.5%壳聚糖涂膜处理对常温货架期翠冠梨果实的保鲜效果最佳。     

壳聚糖涂膜对冷藏白凤水蜜桃品质变化的影响

以“白凤”水蜜桃为试材,研究壳聚糖涂膜对冷藏白凤水蜜桃品质变化的影响。结果表明:白凤水蜜桃贮藏在1±0.5℃低温下时,1.0%壳聚糖涂膜处理可以抑制呼吸强度、多酚氧化酶(PPO)活性及过氧化物酶(POD)活性,还原糖和可溶性固形物含量较低,总酸和总糖含量较高。     

壳聚糖结合气调包装对樱桃萝卜保鲜的研究

研究壳聚糖结合气调包装对樱桃萝卜品质的影响。采用在5℃冷藏条件下,结合气调包装(气体比例3%O2,5%CO2,92%N2)和0.5%、1%、1.5%的壳聚糖溶液涂膜的方法对樱桃萝卜进行保鲜。结果表明:以1.5%壳聚糖结合气调包装处理的效果较好,可降低樱桃萝卜的失重率、糠心率和过氧化物酶活性以及延缓果实硬度下降。同时由于降低了呼吸作用,从而减少VC的氧化和可溶性糖的损失。壳聚糖结合气调包装的储藏方法可以有效地提高樱桃萝卜的保鲜效果。     

不同涂膜处理对鲜切铁棍山药品质的影响

以壳聚糖和海藻酸钠为保鲜剂,对鲜切铁棍山药进行涂膜保鲜,每隔2d测定失重率、Vc含量、可滴定酸含量、褐变度、可溶性固形物含量、多酚氧化酶活性等指标研究保鲜效果。同时以空白组、壳聚糖涂膜组作为对照。结果表明:壳聚糖浓度为1.2%的单一膜和1.2%壳聚糖、0.2%海藻酸钠复合膜都能有效地抑制鲜切铁棍山药的褐变,降低失重率,减少营养物质的损失。复合膜的保鲜效果最好。     

Effects of chitosan coating on postharvest life and quality of longan fruit

The effects of chitosan coating in extending postharvest life of longan fruits and maintaining their quality were investigated. The fruits were treated with aqueous solutions of 0.5, 1.0 and 2.0% chitosan, respectively, and then stored at 2°C and 90% relative humidity. Changes in respiration rate, polyphenol oxidase (PPO) activity, colour, eating quality, and weight loss were measured. The effect of chitosan coating on disease incidence was also evaluated. The application of chitosan coating reduced respiration rate and weight loss, delayed the increase in PPO activity and the changes in colour, and eating quality, and partially inhibited decay of fruit during storage. Furthermore, increasing the concentration of chitosan coating enhanced the beneficial effects of chitosan on postharvest life and quality of the fruit.     

海藻酸钠复合涂膜对贡柑保鲜效果的影响

以海藻酸钠、壳聚糖和尼泊金复合酯为涂膜材料,采用不同涂膜液对新鲜贡柑进行涂膜保鲜,通过测定其感官评价、VC含量、失重率、可滴定酸含量、可溶性固形物含量、可溶性糖含量、过氧化酶(POD)活性等指标进行评定。结果表明,经1%海藻酸钠+0.3%尼泊金复合酯涂膜处理过的贡柑保鲜效果最优,贮藏第35天时,其感官评价5.7分、失重率10.111%、可溶性糖含量8.208%、可滴定酸含量0.367%、VC含量31.301 mg/100 g、可溶性固形物含量10.27%、POD活性0.680 U/g,能较好保持其营养成分,延长货架期。     

Effects of edible coatings on some quality parameters of Chinese water chestnut (Eleocharis tuberosa) during storage

The effects of chitosan and shellac edible coating on the texture, quality attributes and internal changes of Chinese water chestnut (Eleocharis tuberosa) were investigated. Changes in weight loss, respiration rate, cell membrane permeability, oxidase activity and texture profile analysis (TPA) were recorded periodically for 45 days since harvest. Results showed that weight loss, cell membrane permeability and decay rate increased, however, peroxidase (POD), hardness and quality parameters decreased during cold storage. Application of chitosan and shellac coating was determined to give the better results in terms of these analysed parameters compared with the control. Particularly, shellac coating was more effective in reducing weight loss and respiration rate, as well as in maintaining the quality of Chinese water chestnut than chitosan coating.     

Effect of chitosan coating combined with postharvest calcium treatment on strawberry (Fragaria × ananassa) quality during refrigerated storage

Strawberries (Fragaria × ananassa Duch.) were coated with either 1% or 1.5% chitosan (CS) or chitosan combined with calcium gluconate (CaGlu). Following treatment, strawberries were stored at 10 °C and 70 ± 5% RH for one week. The effectiveness of the treatments in extending fruit shelf-life was evaluated by determining fungal decay, respiration rate, quality attributes and overall visual appearance. No sign of fungal decay was observed during the storage period for fruit coated with 1.5% CS (with or without the addition of CaGlu) or 1% CS + 0.5% CaGlu. By contrast, 12.5% of the strawberries coated with 1% CS lacking calcium salt were infected after five days of storage. The chitosan coating reduced respiration activity, thus delaying ripening and the progress of fruit decay due to senescence. Chitosan coatings delayed changes in weight loss, firmness and external colour compared to untreated samples. Strawberries coated with 1.5% chitosan exhibited less weight loss and reduced darkening than did those treated with 1% chitosan, independently of the presence or absence of CaGlu. However, addition of calcium to the 1% chitosan solution increased the firmness of the fruit. Coated samples had greater visual acceptability than had untreated fruits. The addition of calcium gluconate to the chitosan coating formulation increased the nutritional value by incrementing the calcium content of the fruit.     

Effect of chitosan edible coating on the quality of double filleted Indian oil sardine (Sardinella longiceps) during chilled storage

The effectiveness of edible chitosan coating (1 and 2%) on the quality changes of Indian oil sardine (Sardinella longiceps) in iced condition was assessed. The chitosan prepared in the study had higher degree of deacetylation (83%). Edible coating with chitosan was effective in inhibiting bacterial growth and reduced the formation of volatile bases and oxidation products significantly. The muscle pH increased with the storage period for all the samples. On the day of sensory rejection for untreated samples, the formation of total volatile base nitrogen and trimethylamine nitrogen was less by 14.9 and 26.1% for 1% chitosan treated sardine and 32.7 and 49% for 2% chitosan treated samples respectively. The chitosan coating improved the water holding capacity, drip loss and textural properties significantly compared to untreated sample. The eating quality was maintained up to ∼8 and 10 days for 1 and 2% chitosan treated sardine respectively, compared to only 5 days for untreated samples.     

采前涂膜处理对宣化牛奶葡萄贮藏生理及品质的影响

研究采前涂膜处理对宣化牛奶葡萄的采后贮藏生理及保鲜效果。经采前挂蔓涂膜处理的牛奶葡萄在0℃条件贮藏100d,贮藏期间测定了果实的呼吸强度、乙烯释放量、总酚含量、叶绿素含量、可滴定酸含量等生理和品质指标。结果表明：采前涂膜处理可以显著抑制宣化牛奶葡萄果实在贮藏过程中的呼吸强度,处理组果实的呼吸强度比对照低42.5%～53.8%、并在一定程度上减少果实的乙烯释放量;采前涂膜能有效控制葡萄腐烂,贮藏结束时(100d)对照组腐烂率达75.3%,而涂膜处理组的腐烂率只有5.2%。同时可以减少褐变,贮藏75d时处理组的褐变指数比对照低81.6%。保持果实鲜绿色,处理组果实果皮叶绿素含量在50d和75d时为0.04mg/g和0.33mg/g,而对照组则为0.02mg/g和0.015mg/g;也可以保持葡萄果实可溶性固形物、可滴定酸含量,保持感官品质,延长保鲜期约50d。     

Antifungal Coatings on Fresh Strawberries (Fragaria × ananassa) to Control Mold Growth During Cold Storage

ABSTRACT: Chitosan (2%) -based or hydroxypropyl methylcellulose (HPMC) (1%) -based coatings were applied on fresh strawberries to evaluate their antifungal efficacies against Cladosporium sp. and Rhizopus sp. Potassium sorbate (PS) was also incorporated into coating formulas to evaluate any additional inhibitory effects on mold inhibition. Strawberries were inoculated with Cladosporium sp. or Rhizopus sp. at a level of approximately 10³ log colony-forming units (CFU) /g, coated with 2% chitosan, 2% chitosan containing 0.3% PS, or 1% HPMC containing 0.3% PS, and stored at about 5°C and about 50% RH up to 23 d for enumeration of mold, yeast, total aerobes, and coli forms. To assess antifungal activity of the coating materials in vitro, coating solutions were embedded into agar plates and the diameters of radial mold growth were measured after inoculation. In addition, weight loss of coated strawberries and water vapor permeability of the coatings were measured. No significant combined inhibitory effects between chitosan and PS on fungal growth on fresh strawberries were detected. However, significant combined inhibition activity was observed in in vitro testing when PS was formulated into chitosan. Antifungal activity of chitosan against Cladosporium sp. and Rhizopus sp. was not affected by the autoclaving process of coating solutions. Coating treatment also reduced total aerobic count, coliforms, and weight loss of strawberries during storage. Hence, chitosan can be used as a natural antimicrobial coating on fresh strawberries to control the growth of fungi, thus extending shelf-life of the fruits.     

Jujube preservation using chitosan film with nano-silicon dioxide

The effect of 1% chitosan film with 0.04% nano-silicon dioxide on the qualitative properties of harvested jujube under ambient temperature was investigated. After 32 d, the red index, decay incidence, weight loss, and respiration rate of the coated jujubes were lower compared with those of the control. The lower phenylalnine ammonialyase activity and higher activities of scavenger antioxidant enzymes (i.e., superoxide dismutase, peroxidase, and catalase) of the coated jujubes can be attributed to the compound coating. Increased malonaldehyde in the coated jujubes was restrained. Composite coating had shown to be superior in preserving total flavonoid than chitosan coating alone. But no differences were observed in terms of vitamin C loss and total polyphenol content between composite coating and control. Coating jujubes with chitosan + nano-silicon dioxide will be a promising alternative if nano-silicon dioxide is allowed for food use.