预贮和薄膜包装对大久保桃贮藏品质及褐变的影响

为探讨改善桃果实贮藏品质的方法,以大久保桃为试材,研究了30μm厚度的PVC薄膜包装和8℃（冷害温度以上）预贮5d再于0oc（冷害温度以下）冷藏处理对桃果实品质的影响。结果表明,与不包装（对照）相比,包装处理能有效抑制桃果实的软化,保持较稳定的可溶性固形物含量（SSC）和出汁率,明显抑制果实细胞膜透性的增加和果肉褐变：与8℃和0℃直接贮藏相比．经8℃预贮5d后再于O℃冷藏处理不仅可保持良好的果实硬度．贮藏后期SSC和出汁率处于较高的水平．而且能显著降低果实相对电导率和褐变指数．有效改善大久保桃的贮藏性能．保持果实良好的贮藏品质。     

自发气调包装对阿巴特梨冷藏效果影响的研究

冷藏条件下,采用0．02mm厚的聚乙烯袋（PE）薄膜和0．04mm厚的低密度聚氯乙烯（PVC）薄膜为包装材料贮藏阿巴特梨,研究了自发气调包装（MAP）对果实生理变化的影响。结果表明：MAP贮藏可有效抑制阿巴特梨果实乙烯释放量和呼吸强度,抑制果实硬度和可溶性固形物含量下降,延缓果实的衰老进程,降低果实的病果率与黑皮指数,MAP对阿巴特梨有较好的保鲜效果。其中,以0．04mm厚的PVC袋包装保鲜效果较好。     

Chitosan applications pre- or postharvest prolong raspberry shelf-life quality

Raspberries are fruit with high metabolism that makes them very perishable, impairing their storage and shelf-life. Chitosan coatings have the potential to improve their postharvest life by reducing water loss, respiration rate and decay incidence. The purpose of this work was to study the effect of different concentrations of chitosan, applied pre- or postharvest, on the retention of quality attributes of fresh raspberries. The chitosan concentrations tested were 0 (control), 0.5, 1.0 or 2.0%. The postharvest treatment was applied immediately after harvest, dipping the fruit in the solutions for 5 min. The pre-harvest treatment was done with one hand-spray application per week for three weeks, starting when the fruit were just turning pink. In both experiments the fruit were stored at 0 °C and 90% RH. Pre- or postharvest use of chitosan at 1 or 2% was effective in maintaining titratable acidity and retarding respiration and ethylene production, weight loss and decay incidence. Application by both means resulted in the highest chitosan concentrations accelerating a reduction of ascorbic acid contents. Firmness was maintained only when the fruit were treated pre-harvest at 2%. Thus, application of chitosan at 1 or 2% postharvest and 2% pre-harvest was able to retain key raspberry quality attributes for 15 and 12 days, respectively.     

不同保鲜膜对平菇保鲜效果的影响

为比较不同保鲜膜对平菇保鲜效果的影响,分别以低密度聚乙烯(LDPE)膜、高密度聚乙烯(HDPE)膜和聚氯乙烯(PVC)膜为包装材料,在模拟超市冷鲜货架温湿度条件[温度约(14±1)℃,贮藏环境相对湿度约85%]下,研究3种不同保鲜膜对平菇的保鲜效果。结果表明：与LDPE膜相比,HDPE 膜和PVC 膜能降低平菇的采后失重率,维持包装内较高的CO₂体积分数和较低的O₂体积分数;在贮藏的前4天,HDPE膜和PVC膜包装的平菇感官分值与LDPE膜包装平菇无显著差异(P>0.05);但贮藏4天后,HDPE 膜和PVC膜包装的平菇其感官分值明显低于LDPE膜,且呼吸强度及细胞膜透性也显著高于LDPE膜(P<0.05)。3种不同保鲜膜以LDPE膜对平菇的保鲜效果最佳。     

Effect of oxalic acid on ripening attributes of banana fruit during storage

The effect of exogenous oxalic acid treatment on ripening attributes of banana fruit during storage was investigated. Banana fruit were dipped into solutions of 0 (control) or 20 mM oxalic acid for 10 min and then stored at room temperature (23 ± 2 °C) and 75–90% relative humidity. The application of oxalic acid reduced fruit deterioration during storage. The oxalic acid treatment also reduced the rates of respiration and ethylene production, and delayed the decreases in firmness, hue angle, and maximal chlorophyll fluorescence (Fv/Fm) of banana fruit during storage. Furthermore, fruit treated with oxalic acid exhibited higher superoxide dismutase activity and antioxidant capability with a lower production of reactive oxygen species at the late storage period compared with non-oxalic acid-treated fruit. Overall, the oxalic acid treatment was effective in inhibiting postharvest ripening of banana fruit and exhibited the potential for commercial application to store the bananas at room temperature. It can be concluded that the delay in banana fruit ripening associated with oxalic acid treatment could be due to inhibition of respiration and ethylene production rates, and reduction of oxidative injury caused by reactive oxygen species through increased antioxidant activity.     

不同保鲜膜包装对"玉露"水蜜桃保鲜效果的影响

以奉化"玉露"水蜜桃为试材,在研究0.05 mm厚PE防雾保鲜膜(SY)、0.02 mm厚PE保鲜膜(PE)和微孔保鲜膜(W)包装内O2和CO2浓度变化的基础上,研究了三种不同保鲜膜包装对"玉露"水蜜桃保鲜效果的影响.结果表明,三种保鲜膜的通透性存在差异,透气性SY＜PE＜W,SY在保水性方面优于其他两种膜.在(1±0...     

1-MCP对贮藏酥梨品质的影响

为了延长贮藏酥梨货架期品质,以酥梨果实为试材,研究了0.5 μL/L和1.0 μL/L 1-MCP 2种浓度对通风库贮藏酥梨货架期品质的影响。处理果实与对照相比,能较好维持原有外观品质;处理果实呼吸强度和乙烯释放量比对照都有所降低。0.5 μL/L处理效果较明显,果实呼吸强度最低比对照降低24%;1 μL/L处理乙烯释放量最低比对照降低53%,0.5 μL/L处理比对照最低下降了31%。1-MCP处理能延缓果实硬度和可溶性固形物的下降,0.5 μL/L处理果实硬度平均比对照高4.6%,1.0 μL/L处理果实硬度平均比处理高8.6%;0.5 μL/L处理果实可溶性固形物含量与对照有明显差异,最低可下降13%。综合来看,0.5 μL/L对延长地下通风库酥梨货架期有较好的效果。     

1-MCP对冬枣常温贮藏生理和品质的影响

以白熟期冬枣为试材,经不同浓度1-MCP（250,500,1000nL/L）处理后,在常温条件下贮藏30天时,1-MCP处理能够显著抑制冬枣乙醇积累,保持较好的硬度、可溶性固形物和VC含量,降低腐烂指数和乙烯释放速率,提高贮藏后期呼吸速率,但对失水率和转红指数的影响不显著。不同浓度1-MCP处理以1000nL/L保鲜效果最佳。     

Measurement of avocado softening at various temperatures using ultrasound

The low-temperature storage of avocado affects its subsequent softening process and shelf life. One of the main indices of ripeness in avocado fruit is firmness, which changes during the ripening and softening process. The temperature and duration of storage fundamentally influence the firmness of the stored fruit, and monitoring the softening of fruit enables us to regulate its shelf life. The objective of the present study was to use nondestructive ultrasonic tests to elucidate the influences of storage temperature and time on the softening process of avocado fruit. The attenuation of the ultrasonic waves transmitted through the fruit tissue changes as the fruit passes through the various softening stages during and after low-temperature storage. Four groups of avocados, each stored at a different low temperature, and a control group which was stored at room temperature (20°C) were examined during and after their designated storage times, until they reached full ripeness at room temperature. Nondestructive ultrasonic tests and destructive penetration measurements were carried out in order to determine the attenuation and the tissue firmness, respectively, of the avocados. Statistical analysis showed quite good correlation between the firmness and the ultrasonic attenuation, and their dependence on previous storage time-temperature history. This suggests that the ultrasonic measurements could be used as a nondestructive method of monitoring avocado ripeness during low-temperature storage.     

1-MCP对蟠桃采后生理效应的影响

以蟠桃(Prunus perisica L.)为试材,研究了果实采后1-甲基环丙烯（1-MCP）处理对果实营养成分、呼吸强度、果胶酶(Pectase)、多酚氧化酶(PPO)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及果实硬度的影响。结果表明,1-MCP处理能够延缓果实酸度的降低,增加维生素C的含量,对可溶性固形物的变化没有影响;降低呼吸强度,抑制呼吸跃变的发生;抑制果胶酶的活性,延缓果实硬度的下降;处理前期对过氧化物酶的活性有抑制作用。贮藏后期使多酚氧化酶活性增加。0.25μl/L1-MCP处理使过氧化氢酶活性增加。     

Active label-based packaging to extend the shelf-life of “Calanda” peach fruit: Changes in fruit quality and enzymatic activity

Nectarine fruit after cold storage soften normally, but become dry instead of juicy and can develop flesh browning, bleeding and a gel-like or glassy formation of the flesh near the pit. An experiment was conducted to see if time-resolved reflectance spectroscopy could distinguish these internal disorders non-destructively. The optical parameters of absorption coefficient (μ_a) and reduced scattering coefficient (μ′_s) were measured at 670 nm and 780 nm, on nectarine (Prunus persica cv. Morsiani 90) fruit held at 20 °C after harvest or after 30 d of storage at 0 °C or 4 °C. Each day for 5 d 30 fruit were examined both non-destructively and destructively. Other measurements were firmness with a penetrometer, peel colour on the blush and non-blush side, expressible juice, weight loss, and visual rating of internal browning, bleeding, and gel. The fruit had been sorted at harvest according to the value of μ_a670 so that each batch had a similar spread of fruit maturity. More mature fruit (lower μ_a670 values) developed internal browning and bleeding with more severe symptoms compared to less mature ones (higher μ_a670 values). It was found that μ_a780 could distinguish healthy fruits from the chilling injured ones. Canonical discriminant analysis indicated that fruit without cold storage had low μ_a780, less water loss, low firmness, but high μ_a670 and high expressible juice compared with cool stored fruit. Fruit cool stored at 4 °C had high μ_a780 and less expressible juice, lower water loss and lower firmness compared with fruit cool stored at 0 °C. It was concluded that time resolved reflectance spectroscopy could detect internal woolliness and internal browning in nectarines after storage.     

不同果袋处理对红富士苹果贮藏生理的影响

研究了套5种类型果袋对红富士苹果(Malus domestica cv. Red Fuji Spur)低温(0℃)贮藏品质的影响,部分果袋进行早套袋(6月10号)和晚套袋(6月23号)两个处理。各种套袋果实的呼吸速率和失水率在贮藏的第一个月内逐步提高达到峰值,其中套塑膜袋果实的呼吸速率比套小林袋的高47%,同时伴随着可滴定酸、可溶性糖以及硬度的持续降低;随后的一个月内呼吸受到明显抑制,各种品质指标下降缓慢,但在其后的贮藏时间里呼吸速率再次缓慢上升。套塑膜袋的果实仍具有较强的呼吸,晚套袋的果实比早套袋的呼吸略高。贮藏结束时(120d)套小林袋红富士的可滴定酸和果实硬度分别为0.2087%、9.43kg/cm2,套塑膜袋的分别为0.1812%、8.12kg/cm2。综合贮藏过程中果实的呼吸、糖、酸、硬度等指标的变化结果可以看到,不同果袋以套塑膜袋的果实品质下降最大,套小林袋(KM-2)的果实品质下降最小,其次是双层内红袋、双层内黑袋,再次是双层内塑袋。     

Changes in antioxidant activity and postharvest quality of sweet pomegranates cv. Hicrannar under modified atmosphere packaging

The effects of different modified atmosphere packaging (MAP) on antioxidant compounds and storage quality of ‘Hicrannar’ sweet pomegranates were investigated during long term storage. Pomegranates were harvested at the commercial harvest stage and packed in two different types of MAP (MAP1 and MAP2). After packaging, all fruit were stored at 6 °C and 90–95% RH for 120 days, then removed from storage for different quality analyses. Some fruit were kept at 20 °C for 3 days to simulate a period of shelf-life. Fruit weight loss, decay index, skin color, total titratable acidity, total soluble solids content, total phenolics, total anthocyanins and antioxidant activity were determined. Internal atmospheres created by the MAP were periodically assessed during cold storage, and CO₂ concentrations increased and O₂ concentrations decreased inside the MAP. MAP significantly reduced weight loss after both 120 days of cold storage and shelf-life. MAP2 was the most effective packaging in reducing weight loss. Storage of pomegranates in MAP also reduced decay and the decay index, and maintained visual appearance compared to control fruit. During storage, a decrease in L* and C* values and an increase in h° values were observed in all treatments. However, fruit stored in MAP2 had higher L*, C* and lower h° values than in other treatments. Titratable acidity and total soluble solids decreased after cold storage and shelf-life, and no significant differences among treatments were found. Total phenolics, total anthocyanin contents and antioxidant activity increased during the storage period in control fruit.     

不同处理方式对黄花梨果实贮藏效果的影响

摘要：本文研究了在低温下（0℃）不同的保鲜方式,不同成熟度的黄花梨果实,不同的采收方式等因素对黄花梨果实贮藏效果的影响。实验结果表明：在0℃下,黄花梨果实的呼吸高峰推迟,果实硬度维持时间较长,腐烂率明显下降,有效地延长了黄花梨果实的贮藏时间。而且,黄花梨果实在八成熟时选择阴天采摘,在0℃下可以贮藏85天以上,且品质较好。     

Effectiveness of 1-MCP treatments on ‘Bartlett’ pears as influenced by the cooling method and the bin material

Wooden bin-stored ‘Bartlett’ pears (Pyrus communis L.) were hydrocooled (HC) or forced-air cooled (FAC) and immediately treated or not with 1-methylcyclopropene (1-MCP) for 24 h. 1-MCP gas concentrations used were 0, 0.3 or 0.6 μL L^?1 (called 0, 0.3 and 0.6, respectively). Fruit were subsequently kept at 20 °C for 20 d or stored at ?0.5 °C and 95% RH for 60, 90, 120 or 150 d. After cold storage, fruit were kept at 20 °C for up to 16 d for further ripening. In another experiment, pears stored in wooden bins (W) or plastic bins (P) were all hydrocooled, treated or not with 0.5 μL L^?1 1-MCP (called 0.5 and 0, respectively), stored at ?0.5 °C and 95% RH for 0, 30, 60, 90 or 120 d, and transferred to 20 °C for further ripening. In FAC pears, increasing 1-MCP concentrations usually resulted in delayed increases in ethylene production and lower ethylene production rates, as well as delayed softening. In contrast, HC-0.3 pear firmness did not differ from that of HC-0 fruit after cold storage. Generally, HC-0.3 pears displayed higher ethylene production and lower firmness values than FAC-0.3 pears after a 7-d exposure to 20 °C, regardless the length of cold storage. FAC-0.6 pears always showed lower ethylene production rates and higher flesh firmness values than HC-0.6 fruit. Soluble solids concentration was not consistently affected by 1-MCP. FAC-0.3 and HC-0.6 fruit showed higher titratable acidity values than HC-0 fruit after 0, 60, 120 and 150 d of cold storage plus 7 d at 20 °C. Effectiveness of 1-MCP treatments on HC pears was influenced by the bin material; P-0.5 pears were firmer than W-0.5 pears after 7 d at 20 °C, regardless the length of the cold storage. HC-0.5 fruit exposed to ?0.5 °C for 90 d reached eating quality (firmness ≤23 N) by day 7 if placed in W, and by day 21 when stored in P. Results and previous evidence suggest that wet wooden bin material may represent a major though unpredictable source of 1-MCP sorption that could bind a significant percentage of the 1-MCP applied. When used at relatively low doses 1-MCP partial removal by wet wooden bins can compromise the application effectiveness for controlling ethylene action.     

Moisture loss is the major cause of firmness change during postharvest storage of blueberry

Blueberry softening is known to be influenced by cell wall modifications accompanying ripening but these changes appear to be largely complete by the time of harvest. In this study postharvest storage conditions were controlled so only the extent of water loss varied between treatments. A linear relationship between weight loss and loss of firmness (as assessed by a non-destructive compression test) was demonstrated. This relationship did not hold at very low weight loss, where instead, firming of blueberries during storage was found. Magnetic resonance imaging of berries confirmed significant shrinkage and loss of water in berries which had high weight loss, compared with more subtle effects on sub-epidermal water content in berries with very low weight loss. Treatments which restrict blueberry water loss to below 8% are likely to be beneficial in retaining acceptable berry firmness for up to three weeks’ storage.     

采后包装对黄冠梨冷藏期间品质和果皮褐斑的影响

采用纸和薄膜包装的方式对黄冠梨进行冷藏期间品质与预防果皮褐斑病发生试验处理。结果表明,包装能够减少冷藏期间黄冠梨果皮褐斑（又称鸡爪病）发生。纸包装对黄冠梨果实硬度和可溶性固形物含量影响不显著;薄膜包装能在一定程度上保持黄冠梨较高的果实硬度,降低可溶性固形物含量、果皮酚含量和多酚氧化酶活性,以PVC薄膜包装方式较为理想。     

Effect of calcium dips and chitosan coatings on postharvest life of strawberries (Fragaria x ananassa)

Strawberries (Fragaria x ananassa Duch.) were treated either with 1% calcium gluconate dips, 1.5% chitosan coatings or with a coating formulation containing 1.5% chitosan + 1% calcium gluconate and stored at 20 °C for up to 4 days. The effectiveness of the treatments was assessed by evaluating their impact on the following parameters: fungal decay incidence, loss of weight, firmness, external color, pH, titratable acidity and soluble solids content. Calcium dips were effective in decreasing surface damage and delaying both fungal decay and loss of firmness compared to untreated fruit. No sign of fungal decay was observed in fruit coated with 1.5% chitosan which also reduced fruit weight loss. Chitosan coatings markedly slowed the ripening of strawberries as shown by their retention of firmness and delayed changes in their external color. To a lesser extent titratable acidity and pH were also affected by coatings. Whilst addition of calcium gluconate to the chitosan coating formulation did not further extend the shelf-life of the fruit, the amount of calcium retained by strawberries was greater than that obtained with calcium dips alone, thus resulting in increased nutritional value of the strawberries.     

Respiration rate,ethylene production and biochemical variations of ackee fruit arils (Blighia sapida Köenig) stored under three temperature regimes

The storage of fruit is characterized by many physiological and biochemical changes, and this study aimed to study respiration rate, ethylene production, and other biochemical variations of ackee fruit arils (Blighia sapida), cheese variety, stored at 5, 10 and 20 °C during eight days. During storage, respiration rate decreased but ethylene production increased. Glucose, fructose, sucrose, and short chain fructooligosaccharides – 1-kestose, nystose and DP-5 – and total phenolic compounds also decreased, however, the decrease was much higher at 20 °C. The L*, a*, b, C* and H* values showed that lower temperatures preserved much better colour and visual quality, and arils stored at 5 °C were rated excellent compared to those stored at 10 and 20 °C. The quality of arils stored at 10 °C also was more than satisfactory, while arils stored at 20 °C were completely spoiled after 8 days and showed high weight losses compared to arils stored at 5 and 10 °C, which did not show any spoilage and very low weight losses. In conclusion, the results demonstrated that ackee fruit arils can be stored in very good conditions for a minimum of eight days under low temperature regimes, although at 5 °C arils showed the best shelf-life.     

Effect of harvest maturity on quality of fresh-cut pear salad

Texture of an unripe pear is firm and crisp, similar to an apple. However, at the crisp stage, the flavor of pears is flat. This study evaluated the effect of harvest maturity on the quality of fresh-cut pear salad. Fruit were harvested at commercial maturity and 1-month delayed. After 2 and 5 months (1 and 4 months for delayed-harvest fruit) storage at ?1 °C, fruit were sliced into 8–12 wedges per fruit, dipped in an antibrowning solution, packaged in Ziploc bags and stored at 1 °C for up to 21 d. Delayed-harvest fruit were larger in size (≈20% increase in weight), had lower flesh firmness (≈17% decrease), lower titratable acidity content (≈20% decrease), and lower phenolic content (≈45% and 13% decreases in pulp and peel, respectively). There was no significant difference in soluble solids content. After 2 months storage, ethylene production and respiration rate were initially lower in the slices from delayed-harvest fruit, but tended to become similar after 7 d in storage at 1 °C. Delayed-harvest fruit had lower hydroxycinnamic acids and flavanols, and higher ester, alcohol, and aldehyde volatile compounds after 2–5 months storage. The results indicated that fruit salad produced with delayed-harvest pears had less browning potential and better flavor. Sensory evaluation results showed that about 80% of the panel liked slices from delayed-harvest fruit over commercial harvested, especially in terms of visual quality (65–85%), sweetness (75–95%), taste (70–80%), and overall quality (75–80%) during 21 d storage at 1 °C. The cut surface of slices appeared dry in delayed-harvest fruit when processed after 5 months in storage. However, sensory evaluation showed that panels still preferred the delayed-harvest fruit.