Quality changes in sapote mamey fruit during ripening and storage

Physical and chemical changes in sapote mamey (Pouteria sapota (Jacq.) H.E. Moore and Stearn) fruit during ripening and storage at various temperatures were evaluated. Ripening was associated with flesh softening, an increase in soluble solids content (SSC), and a change in flesh color from yellow or pale pink to a dark pink or red. No changes in fruit skin color or in flesh acidity were observed as ripening progressed. Ripe fruit had 30% or higher SSC, orange or red flesh (hue angle=52; chroma=45; L=60), acidity of 6–8 mM H⁺, and flesh firmness (compression force) ≤50 N. Flesh turned brown (L* value declined) in overripe fruit. Fruit held at 27, 25, or 20°C ripened in 3.5, 5 or 7 days after harvest, respectively. Fruit kept at 10°C showed minor changes in color and firmness and a slow rate of SSC increase. Fruit stored at 10 or 15°C and then ripened at 20°C had portions of the flesh with a much higher firmness and poorer development of red color compared to other parts of the fruit. This uneven ripening was probably a result of chilling injury. The number of fruit with injury was higher at 10°C than at 15°C, and increased with storage time. The rates of fruit weight loss relative to the initial fruit weight were 0.58, 0.98 and 1.83% d⁻¹ at 10, 20 and 27°C, respectively.     

Effect of 1-methylcyclopropene on ripening of ‘Canino’ apricots and ‘Royal Zee’ plums

‘Canino’ apricots and ‘Royal Zee’ plums were treated with 1000 nl l⁻¹ 1-methylcyclopropene (1-MCP) at 20 °C for 20 h following harvest before 0 °C storage. After 5 days storage for apricots and 10 days for plums and after 30 days storage for both, fruit were moved to 20 °C for ripening. In addition, apricots were stored for 20 days and then treated with 1-MCP concentrations of 10, 100 and 1000 nl l⁻¹ at removal and held for ripening. Ethylene production and respiration rate, as well as fruit quality of apricots varied with treatment. Ethylene production was efficiently inhibited by 1000 nl l⁻¹ 1-MCP in fruit treated after storage but not in fruit treated before storage. Fruit softening was associated with ethylene production and affected by 1-MCP in a concentration dependent manner when treated after storage, while 1-MCP did not affect softening in prestorage treated fruit. The color change of fruit was ethylene-independent and not affected by 1-MCP. Internal flesh browning was decreased by 1-MCP regardless of the concentration when treated after storage, while it was enhanced in fruit treated before storage. Decay development in apricots was decreased by 1-MCP in a concentration dependent manner. Ethylene production and respiration in ‘Royal Zee’ plums was greatly inhibited by 1-MCP during ripening after both short-term (10 day) and long term (30 day) storage. Parameters associated with ripening processes were decreased significantly by 1-MCP, including softening, color change, and loss of titratable acidity. These data demonstrate that 1-MCP has potential to delay ripening of apricots and plums, but the cultivar, maturity of fruit, and time of application must be chosen carefully. It is suggested that 1-MCP is more efficient for extending the shelf life and improving the quality of ‘Canino’ apricots directly marketed or after storage, whereas it might be a potent compound for extending both storage period and shelf life of ‘Royal Zee’ plums.     

库尔勒香梨采后特征品质的研究

摘要：库尔勒香梨贮藏在0℃、5℃、10℃、15℃、20℃,相对湿度：90～95%的环境中,测定香梨在贮藏过程中果实硬度、可溶性固形物含量及果皮色泽的变化,采用数值的极差及变异系数,研究采后库尔勒香梨的特征品质。结果表明：香梨采后贮藏于不同温度下,其硬度随着果实的成熟均呈现下降趋势,低温贮藏对硬度的下降有明显的抑制作用;可溶性固形物在不同贮藏温度下降不明显,特别是低温贮藏;果品色泽在各贮藏温度下,随着贮藏时间的延长,成熟度增加,有显著的变化。比较香梨果实硬度、可溶性固形物、色差的在整个贮藏期间的变化差异,色差的数值变化最为明显,对香梨采后品质及衰老具有明显的指示作用,可作为评价香梨果实采后品质变化的特征指标及采后衰老的重要指标。     

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。     

不同采收成熟度对阿巴特梨后熟过程中品质变化的影响

以阿巴特梨为试材,研究三个采收期的果实在后熟过程中的生理变化以及各品质指标间的相互关系。结果表明,在后熟过程中,各采期的果实均出现了明显的乙烯和呼吸高峰,其中采期Ⅱ(盛花后132 d)果实的乙烯和呼吸释放量最高。随着采期的延后,果实硬度逐渐下降,可溶性固形物含量逐渐升高,反映果皮颜色的H°值逐渐下降,L*和a*值逐渐升高,果实相关品质指标与果皮颜色呈显著相关性。总体上看,以采期Ⅱ果实的后熟品质最佳。     

Postharvest physiology and browning of longkong (Aglaia dookkoo Griff.) fruit under ambient conditions

Longkong (Aglaia dookkoo Griff.) fruit rapidly loses its yellow skin color and turns brown after harvest. We aimed to elucidate the postharvest physiology and browning mechanism of longkong fruit stored at a 70–85% RH and at room temperature (25 °C). The respiration rate slightly decreased with progressive fruit browning, while ethylene production was dramatically increased. Preliminary experiments showed that ethylene treatment markedly increased peel browning, suggesting that this is induced by ethylene. The peel L-value continuously decreased during storage, in relation to the severity of peel browning. The peel surface morphological data indicated that the ultrastructure of longkong peel collapsed after harvest, especially around brown areas. The total phenolic content of peel tissue rapidly increased, concomitant with rapid increases in phenylalanine ammonia lyase (PAL) activity and browning score on day 2. Tissue from the lower part of the fruit had higher total phenolic contents, as well as polyphenol oxidase (PPO) and PAL activities, compared to the top and middle parts of the fruit; however, peroxidase (POD) activity slightly changed during storage, possibly independent of phenol oxidation. The browning of longkong peel was not associated with changes in soluble solids contents, titratable acidity or ascorbic acid levels.     

不同‘安梨’株系后熟前后果实营养成分变化

选取燕山地区7个‘安梨’株系果实为试材,自然室温下贮藏,研究安梨不同株系后熟前后果实品质的变化。结果表明,‘安梨’后熟后果实软化、硬度降低,是果实结构中果胶和纤维素含量下降的结果。7个‘安梨’株系果实后熟前后可溶性固形物、可滴定酸、酚类物质、石细胞含量均升高,果胶、pH值、固酸比、纤维素含量均下降。在这7个株系中,以东乐村10-7、10-8果实品质最好,几种营养成分含量最高,果实不易褐变;大崔庄11-2果实耐贮藏性最好,贮藏期间营养成分损失少,明显优于其他株系,可以作为优良株系进一步研究。     

冷藏期间小白杏果实后熟过程中相关抗逆特性的表现

以新疆库车小白杏为试验材料,研究在(0±0.5)℃温度、95%相对湿度条件下贮藏36 d的小白杏果实游离脯氨酸含量、细胞膜渗透率、β-1,3-葡聚糖酶、脂氧合酶(LOX)和苯丙氨酸解氨酶(PAL)活性的变化,探讨冷藏处理对小白杏抗逆性的影响,以期为采后小白杏的贮藏保鲜提供一定的理论依据。研究结果表明,在冷藏期间,随着绿熟小白杏的后熟,果实细胞膜渗透率逐渐增加,游离脯氨酸含量总体呈上升趋势,β-1,3-葡聚糖酶、LOX和PAL活性也呈上升趋势,冷藏18~27 d时的果实成熟度转为完熟期,品质最佳;之后进入衰老期,其相关抗性指标迅速下降并有起伏的动态趋势,其机理有待进一步研究。     

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.     

臭氧处理对草莓贮期果实品质的影响

以优质草莓为试材,研究了臭氧处理对草莓贮藏期间品质变化的影响。结果表明,草莓在(2.0±1.0)℃下贮藏,每隔3 d采用质量浓度300 mg/m3的O3处理0.5 h,能有效保持果实可溶性固形物含量和可滴定酸含量,降低果实呼吸强度和腐烂率,较好地保持果实硬度。适宜的臭氧处理对草莓有良好的保鲜效果。     

含迟熟基因rin的番茄果实货架寿命相关性状的研究

分析比较了贮藏过程中的番茄成熟突变体rin材料L2与正常成熟番茄品种L5及其杂种一代L20果实的果实硬度、呼吸强度、番茄红素、贮藏指数及各种商品品质的差异。结果表明:番茄果实贮藏过程中果实硬度呈下降趋势;而果实的可溶性固形物、可溶性糖、Vc、番茄红素含量变化呈上升趋势,但是有机酸含量变化总体上呈现下降趋势,因此果实的糖酸比呈上升趋势;呼吸高峰的出现有很大的差异,L2的波动较小,且呼吸强度一直处于最低状态;rin番茄果实的贮藏指数最高,达到75%以上,而正常成熟的番茄贮藏指数最低,仅60%左右,含迟熟基因的品种与正常品种杂交后贮藏性显著下降,但比正常成熟番茄耐贮,贮藏指数比正常成熟的高约15%。     

低温贮藏期对芒果果实抗氧化能力和品质的影响

探明低温贮藏期对‘台农1号’芒果(Mangifera indica L．)果实病害、抗氧化水平以及果实品质的影响,以期为采后芒果果实的低温贮藏提供科学的理论依据。以广西百色地区的‘台农1号’芒果为试材,采用10 °低温贮藏果实,分别在贮藏期第0、5、10、15、20、25和30 d时,测定果实中抗氧化能力包括过氧化氢酶、超氧化物歧化酶、苯丙氨酸解氨酶、总抗氧化能力、多酚氧化酶、超氧阴离子、过氧化氢、丙二醛、总酚,和果实品质包括可溶性固形物、可滴定酸、维生素C,以及果实发病情况等指标。结果表明,贮藏期第15 d,芒果病害开始出现,而且,随贮藏期越长,果实腐烂率越高。贮藏前期(15d以前)果实中过氧化氢酶、超氧化物歧化酶、总抗氧化能力和总酚等维持了较高的含量；贮藏后期(20 d以后)果实组织中超氧化物歧化酶、总抗氧化能力和总酚含量显著降低,而丙二醛含量明显增加,同时,果实中可溶性固形物开始下降,可滴定酸含量进一步降低。综合以上结果表明,采用10 °低温贮藏‘台农1号’芒果果实,中短期(20d左右)为宜。     

壳聚糖涂膜对芒果采后品质及生理特性的影响

为了探讨壳聚糖涂膜保持芒果采后品质的相关生理机制,以‘台农1号’芒果(Mangifera indica L.‘Tainong No.1’)为材料,研究了1.0%壳聚糖涂膜处理对芒果在常温(28~30℃)贮藏条件下果实品质及生理特性的影响。结果表明,与对照相比,壳聚糖涂膜处理显著降低了果实的失重率和病果率,延缓了果皮颜色的转黄,保持较高的果实硬度;并且,壳聚糖涂膜有效保持了果实品质,能够显著延缓芒果可滴定酸(TA)含量的降低和可溶性固形物(TSS)含量的升高,维持芒果果实较高的Vc含量;同时,壳聚糖涂膜也提高了芒果果实贮藏后期超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性,并抑制MDA含量的积累,降低膜脂过氧化程度,从而延缓了采后芒果的后熟衰老进程。     

两个杏品种不同成熟期果实品质变化研究

以金太阳(Prunus armeniaca Golden-sun)和魁金杏(Prunus armeniaca Kuiijn)为试材,研究其在绿熟期、商熟期和完熟期果实中类黄酮、类胡萝卜素等品质指标的变化。结果表明：两个杏品种果实单果重、可溶性固形物、Vc含量、可溶性糖、类黄酮和类胡萝卜素含量均随着果实的成熟不断升高,在完熟期达到最高,魁金高于金太阳;果实硬度和有机酸含量均随着果实成熟度的增加而降低,在完熟期达到最低,魁金低于金太阳,魁金果实品质优于金太阳。     

Residual effects of low oxygen storage of mature green fruit on ripening processes and ester biosynthesis during ripening in bananas

Mature green banana (Musa sapientum L. cv. Cavendish) fruit were stored in 0.5%, 2%, or 21% O₂ for 7 days at 20 °C before ripening was initiated by ethylene. Residual effects of low O₂ storage in mature green fruit on ripening and ester biosynthesis in fruit were investigated during ripening for up to 6 d at 20 °C. Concentrations of ethanol in mature green fruit did not change during storage in both 21% and 2% O₂ atmospheres, but increased in fruit stored in 0.5% O₂. The activities of alcohol dehydrogenase (ADH) in 2% and 21% O₂ atmospheres remained very low throughout the storage period, but significantly increased with 0.5% O₂. After transferring fruit to regular air and trigging ripening with ethylene, yellowing of peel, fruit softening and hydrolysis of starch in fruit stored in low O₂ atmospheres were slower than in the control. Fruit stored in low O₂ also showed a delayed onset of the climacteric peak. The activities of ADH were lower in the low O₂ stored fruit than in the control fruit. Productions of ethyl acetate, isoamyl acetate, and isobutyl acetate were remarkably suppressed by low O₂ storage. Alcohol acetyltransferase activity increased gradually with storage time in all treatments, being significantly lower in fruit with low O₂ pretreatments. The results indicate that low O₂ plus room temperature storage can extend storage life of bananas with the sacrifice of a low production of ester volatiles.     

Effect of gum arabic as an edible coating on antioxidant capacity of tomato (Solanum lycopersicum L.) fruit during storage

Coating of tomato fruit with gum arabic has been found to delay the ripening process and maintain the antioxidant capacity. Gum arabic in aqueous solutions of 5, 10, 15 and 20% was applied as an edible coating to green-mature tomatoes which were stored at 20 °C and 80–90% RH for 20 days. Fruit coated with 10% gum arabic delayed the ripening process by slowing down the rate of respiration and ethylene production and also maintained total antioxidant capacity, lycopene content, total phenolics and total carotenoids during storage as compared to the uncoated control and fruit treated with 5% gum arabic concentration. The results suggest that by using 10% gum arabic as an edible coating, the ripening process of tomatoes can be delayed and the antioxidant can be preserved for up to 20 days during storage at 20 °C without any negative effects on postharvest quality.     

Methods to analyze physico-chemical changes during mango ripening: A multivariate approach

Canonical discriminant analysis (CDA) was used to identify the best method to discriminate between maturity and ripening stages, assessed in terms of dry matter content, firmness, color (peel and flesh), total soluble solids content attributes, before and during ‘Keitt’ mango ripening at 20 °C. Dry matter content was determined by hot-air oven and microwave oven methods. Fruit firmness was determined non-destructively by hand squeezing, with a durometer, using acoustic resonance and low-mass elastic impact methods (AWETA), as well as destructively by the penetrometer. Peel and flesh color were expressed as L*, a*, b*, h⁰ and C* values. Total soluble solids content was analyzed from filtered juice from whole fruit tissue and from unfiltered juice squeezed out by hand. Canonical discriminant analysis indicated that the durometer and the penetrometer were better methods to assess firmness than hand firmness, acoustic resonance or impact methods. The best color attributes to follow changes during early stage of ‘Keitt’ mango ripening were a* and b* values of the flesh, whereas b* value of the peel was considered better during later stages of ripening. Results of total soluble solids content in filtered juice from whole fruit tissue were less variable compared to unfiltered juice squeezed out by hand. Dry matter content was better assessed by drying the sample in a microwave oven than in a hot-air oven. A combined CDA including the best methods to assess each ripening attribute, as well as titratable acidity, showed that the best tools to assess changes in fruit during ripening were the penetrometer, followed by flesh a* value and total soluble solids content (from filtered juice from whole fruit).     

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.