不同贮藏条件对山竹果皮木质化效应及抑菌活性影响

以海南山竹为材料,研究了不同贮藏条件对山竹果皮木质化及抑菌活性影响。结果表明:随着贮藏时间的延长,山竹果壳木质素沉积指标木质素含量和粗纤维含量均呈上升趋势。贮藏末期,常温处理的木质素含量比同期壳聚糖、海藻酸钠和低温处理的木质素含量分别增加6.0%、2.8%和14.3%。木质化底物总酚含量呈先升后降趋势,在第6天达到峰值,为33.033 mgGAE/g(鲜重),抑菌活性表明,在贮藏期间,山竹果皮抑菌活性因受木质化产物和多酚转化产物的影响有不同的变化趋势,低温和涂膜有助于抑菌活性稳态化。     

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。     

壳聚糖涂膜对延缓菜心采后衰老效果的研究

研究了菜心在不同浓度壳聚糖涂膜处理后4℃下贮藏时的质量损失、叶绿素含量、主要营养和过氧化物酶活性的变化。结果表明,与对照相比,壳聚糖涂膜处理明显减少了菜心的质量损失,延缓了菜心的叶绿素、蛋白质、可溶性总糖及Vc含量的下降速度,降低了过氧化物酶活性。2%和3%的壳聚糖处理显著延缓了菜心采后衰老,延长了冷藏菜心的保鲜期。     

三种可食性涂膜对黄皮货架期品质和生理的影响

研究货架期不同类型的可食性涂膜处理对黄皮品质的影响,为可食性涂膜技术在黄皮贮藏保鲜中的应用奠定基础.以黄皮为试材,经壳聚糖涂膜液、羧甲基纤维素涂膜液、海藻酸钠涂膜液分别处理后在常温下贮藏8d模拟货架期,考察不同涂膜处理对果实的相关生理指标的影响.结果表明,可食性涂膜处理尤其是壳聚糖膜、羧甲基纤维素膜能明显抑制果实的呼吸强度,其中壳聚糖膜可减缓可溶性固形物及可滴定酸含量的下降,显著降低贮藏期间细胞质膜透性及丙二醛含量,抑制膜脂过氧化作用,有效延缓黄皮果实的采后后熟,从而延长黄皮采后货架期.     

魔芋葡甘露聚糖-壳聚糖复合涂膜对北碚447锦橙贮藏品质的影响

为探究魔芋葡甘露聚糖-壳聚糖复合涂膜对北碚447锦橙贮藏品质的影响,分别采用0.5%魔芋葡甘露聚糖+1%壳聚糖复合涂膜,0.5%魔芋葡甘露聚糖涂膜和空白处理北碚447锦橙。以5 d为一个周期,15 ℃温度贮藏,共贮藏5个周期,测定贮藏期间果实的总糖、可滴定酸、V_C、固形物、总酚等指标。结果表明,复合涂膜处理可有效延缓果实品质的下降,与0.5%魔芋葡甘露聚糖涂膜和空白处理对比,复合膜组能够明显抑制果实总糖、可滴定酸、V_C、总黄酮、总酚含量的下降,减缓果实中丙二醛的积累,使锦橙保持了较好的果实品质。证明了复合涂膜处理相比单独0.5%KGM保鲜效果更好。     

不同贮藏方式对马蹄贮藏品质的影响

以马蹄为研究材料,在常温(25±1)℃下,探讨缸藏法、打孔包装(聚乙烯保鲜袋)和2%壳聚糖涂膜处理对马蹄贮藏品质和抗氧化活性的影响。结果表明,2%壳聚糖涂膜处理能更好的维持马蹄TSS、VC和总糖的含量,有效延缓了腐烂和MDA的积累,同时延缓了马蹄POD和SOD酶活性最大值的出现和抗氧化性能的下降,是较好的马蹄贮藏方式。     

不同涂膜处理对水蜜桃常温贮藏品质的影响

以水蜜桃为试验材料,研究壳聚糖、海藻酸钠、普鲁兰多糖浸泡涂膜处理对水蜜桃采后常温下(28℃)贮藏品质的影响,定期测定各项生理指标。结果表明,与对照组相比,3种涂膜处理均能在不同程度上抑制水蜜桃果实的腐烂过程,维持贮藏期果实的品质。海藻酸钠涂膜处理果实能够显著降低果实的腐烂率(比对照组降低40%),同时维持果实硬度、延缓丙二醛含量的上升;壳聚糖涂膜处理在控制果实失重、抑制多酚氧化酶活性方面则优于海藻酸钠和普鲁兰多糖;3种涂膜处理在维持可溶性固形物含量、抑制呼吸方面无显著差异。1%海藻酸钠涂膜处理由于能够显著抑制果实腐烂,延长果实的货架期,保鲜效果相对最佳。     

海藻酸钠涂膜及60Co-γ辐照处理对小枣的保鲜作用

以全红期的山东省乐陵小枣为实验材料,分别进行60Co-γ辐照处理、海藻酸钠涂膜处理及二者结合处理后,与对照组同时于(2±0.5)℃冷库贮藏,并对低温贮藏过程中枣的失重率、总糖、还原糖、VC、可滴定酸含量及糖酸比的变化进行测定。结果表明:涂膜、辐照、涂膜+辐照处理均能有效减少水分散失,延缓VC和可滴定酸的下降,抑制糖酸比的上升,涂膜+辐照处理能保持较高的总糖、还原糖含量。其中,60Co-γ辐照+海藻酸钠涂膜处理于(2±0.5)℃冷库贮藏保鲜效果显著优于其他实验处理组,有助于提高乐陵小枣采后的低温贮藏品质。     

壳聚糖涂膜处理对沙糖桔采后生理及品质的影响

目的研究壳聚糖涂膜处理对沙糖桔(Shatang mandarin)采后生理及品质的影响。方法常温条件下(20±2)℃采用0.5%、1.0%和1.5%壳聚糖涂膜处理,每4 d取一次样品,分别对沙糖桔果实的腐烂率、呼吸强度、可滴定酸含量、可溶性固形物含量和维生素C含量进行测定。结果与对照组相比,不同质量分数的壳聚糖涂膜处理均能有效抑制沙糖桔果实腐烂率的上升,延缓呼吸强度、可滴定酸、可溶性固形物和维生素C含量的下降。其中,1.5%壳聚糖涂膜处理对维持沙糖桔果实采后生理及品质的效果更显著。结论常温条件下,1.5%壳聚糖涂膜处理适用于沙糖桔果实的贮藏保鲜。     

壳聚糖调节膜透性和能量代谢减缓沃柑果实采后品质劣变

壳聚糖是一种具有多重生物活性的天然多糖,可参与生物体多种生理活动。本文研究了2%壳聚糖涂膜处理,对采后沃柑果实在25 ℃贮藏期间,果实贮藏和营养品质、膜透性及能量代谢的影响。结果显示:壳聚糖有效延缓了采后沃柑果实在贮藏期间可溶性固形物含量、总可滴定酸含量的下降,失重率和固酸比的上升;有效抑制了类胡萝卜素、抗坏血酸、总酚和类黄酮含量的下降。研究表明,壳聚糖显著抑制了膜透性上升,表现为贮藏期间果实组织更低的相对电导率和丙二醛含量。此外,壳聚糖通过诱导H+-ATPase、Ca2+-ATPase、琥珀酸脱氢酶、细胞色素C氧化酶活性,使沃柑果实在贮藏期间维持较高的能量状态,表现为三磷酸腺苷和能荷水平上升。结论:壳聚糖能通过调节膜透性和能量代谢,有效维持采后沃柑果实贮藏和营养品质,延缓其采后衰老进程。     

壳聚糖-山竹果皮提取液复合涂膜对蓝莓的保鲜效果

以‘北陆’蓝莓为试材,研究0.5%的壳聚糖（chitosan,CTS）结合1%山竹果皮提取液（mangosteen peel extracts,MPE）处理对其在低温（4±0.2）℃贮藏期间保鲜效果的影响。结果表明,CTS处理和CTS与MPE复合处理均能够减缓蓝莓果实贮藏期间硬度、可溶性固形物（TSS）含量以及含水量的下降,使果实呼吸高峰的出现时间推迟了7 d,减缓维生素C（V_C）含量及总酚含量的下降,同时延缓丙二醛（MDA）含量的上升。在贮藏后期（第49 d）,CTS和MPE复合处理仍使果实维持较高的DPPH·和ABTS +·清除率,分别比对照高8.9%和20.3%,使其保持了较好的抗氧化能力。其中,CTS与MPE复合处理的效果最好。结论:CTS与MPE复合涂膜处理能有效地保持蓝莓果实的贮藏品质及抗氧化活性,延缓其成熟衰老的进程。     

百里香酚/海藻酸钠膜对茄梨贮藏品质的影响

采用海藻酸钠(Sodium Alginate,SA,2%(m/v))和百里香酚/海藻酸钠(Thymol/Sodium Alginate,Thy/SA,Thy终浓度为40 mg/L)涂膜分别对茄梨进行处理,于20℃下进行贮藏,以果实硬度、可溶性固形物含量、抗坏血酸含量、可滴定酸含量、丙二醛含量、多酚氧化酶活性等指标来判断茄梨的品质变化。结果表明,Thy/SA涂膜使得茄梨果实的贮藏期由9 d(对照组)延长至18 d,有效延缓了果实硬度、可滴定酸、抗坏血酸和总酚含量的下降,以及可溶性固形物、丙二醛含量、多酚氧化酶和过氧化氢酶活性的上升。由此可见,Thy/SA涂膜可较好地维持贮藏过程中茄梨的果实品质,进而延长了其贮藏期。     

贮藏温度对山竹果皮硬化效应及抑菌活性影响

本文以海南山竹为材料,研究了贮藏温度(4℃,30℃)对山竹果皮硬化效应及抑菌活性影响。结果表明:随着贮藏期的延长,山竹果壳硬化效应指标木质素含量和粗纤维含量均呈上升趋势。贮藏末期,常温处理的木质素含量比低温处理的木质素含量增加14.3%。木质化底物总酚含量呈先升后降趋势,在第6 d达到峰值,为33.03 mg GAE/g FW,抑菌活性表明,在贮藏期间,山竹果皮抑菌活性因受木质化产物和多酚转化产物的影响有不同的变化趋势,低温有助于抑菌活性稳态化。     

花椒提取液与壳聚糖复合膜对冬枣保鲜效果的影响

以冬枣为试验材料,用2％壳聚糖溶液、50 mg/mL花椒提取液与2％壳聚糖复合溶液对冬枣进行浸泡处理,以清水浸泡为对照,4 ℃低温储藏,每隔5d测定果实的腐烂率、失重率、硬度、可溶性固形物、可滴定酸、维生素C、丙二醛(MDA)、过氧化物酶(POD)活性等品质或生理指标,研究花椒提取液与壳聚糖复合膜对冬枣采后保鲜效果的影...     

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。     

Determination of translucent content in mangosteen by means of near infrared transmittance

Translucent flesh disorder is undesirable in mangosteen meant for export. However, mangosteens are judged as translucent when the translucent flesh is visible on the pulp surface regardless of the quantity of the internal translucent flesh which may result in some mangosteen assessed as normal having the same amount of translucent flesh content as a mangosteen judged as translucent. The critical amount of translucent flesh to be visible on the pulp surface needs to be determined for assessment purposes. A non-destructive technique to measure the translucent content is a practical tool as the first step towards the establishment of the critical value.A non-destructive model was developed to estimate the translucent content in mangosteens using near infrared transmittance. The translucent area of the flesh section on the fruit surface was used to indicate the translucent content. The effects of the orientation of the fruit and also of the light source to the relative position of the detector as well as the effect of the measurement position of the fruit on the predictive performance were examined. The results showed that the best partial least squares model was achieved with spectra acquired from the fruit position which revealed the largest flesh segment (prediction correlation coefficient was 0.86 and root mean square error of prediction was 7.58%). The horizontal stem-calyx fruit axis and a 135° angle from the light source relative to the detector were the optimal fruit orientation and configuration for measurement.     

Phenolic acid profiles of mangosteen fruits (Garcinia mangostana)

The composition of phenolic acids in various parts of mangosteen fruit (Garcinia mangostana) was determined by GC and MS. The total content of phenolic acids, identified by GC-FID ranged from 265.7 ± 12.7 (aril) to 5027.7 ± 188.0 (peel) mg per kg of dry matter of sample. Ten phenolic acids were identified in mangosteen fruit. Of these, protocatechuic acid was the major phenolic acid in the peel and rind, while p-hydroxybenzoic acid was the predominant phenolic acid in the aril. m-Hydroxybenzoic acid was detected only in the peel, while 3,4-dihydroxymandelic was present only in the rind. The phenolic acids liberated from esters and glycosidic bonds were the major fractions of phenolic acids in mangosteen fruit.     

Protein-binding and antioxidant potential of phenolics of mangosteen fruit (Garcinia mangostana)

Phenolics were extracted from mangosteen fruit parts with 70% (v/v) aqueous acetone. The yield of crude extracts of phenolics (CP) ranged from 5.8% to 7.9%. The total phenolics (TPH) content ranged from 9.3 mg to over 250 mg of gallic acid equivalents per g of extract in the edible aril and skin, respectively. The formation of phenolic–protein complexes was assayed by both the dye-labelled bovine serum albumin (BSA) and the fluorescence quenching methods. Phenolics from peel and rind displayed a strong protein-precipitating potential. On the other hand, phenolics from edible aril exhibited greater affinity for BSA, as determined by the fluorescence quenching assay. The static quenching was the dominant mode of quenching of BSA fluorescence by mangosteen fruit phenolics. Mangosteen phenolics occupied two binding sites on BSA molecules located most likely in or near both tryptophan residues in the BSA molecule acting as an intrinsic fluorescence probe.