Changes in Radical-scavenging Activity and Components of Mulberry Fruit During Maturation

ABSTRACT Extracts of mulberry fruits (Morus sp.) were prepared from 8 cultivars harvested at 4 stages of maturity, and their radicalscavenging activity, anthocyanin content, and total phenolic content were measured. The radical‐scavenging activity was evaluated by a spectrophotometric assay using the 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH) in a 96‐well microplate. Mulberry fruit extracts exhibited the DPPH‐scavenging activities, ranging from 2.5 to 20.3 μmol‐Trolox equiv/g‐FW. Their activities were variable during maturation, and the highest activity was observed in the fully mature mulberry fruit in all cultivars. Anthocyanin was scarcely present in the immature mulberry fruits; however, its content increased as the fruit matured in all cultivars. On the other hand, all immature mulberry fruits contained non‐anthocyanin phenolic compound. An on‐line high‐performance liquid chromatography (HPLC) method for the detection of DPPH‐scavenging compounds revealed the difference in predominant radical scavengers between the immature and fully mature stages in the Miran 5 cultivar. Four major radical scavengers in the Miran 5 cultivar were assigned to 2 caffeoylquinic acids (chlorogenic acid and its isomer) and 2 anthocyanins (cyanidin 3‐glucoside and cyanidin 3‐rutinoside) in the immature and fully mature stages, respectively, by LC‐ESI‐MS/MS analysis. The change in the content of 4 compounds in mulberry fruits during maturation demonstrated that the most likely contributors to the DPPH‐scavenging activity were caffeoylquinic acids in the immature mulberry and anthocyanins in the mature and fully mature mulberry.     

1- 甲基环丙烯对李果实冷藏及货架期非挥发性风味物质的影响

使用多变量分析方法研究1-MCP对‘黑琥珀’李果实0℃贮藏和随后的20℃货架期间非挥发性的糖、有机酸和氨基酸的影响。单因素试验结果表明：低温贮藏期间,李果实蔗糖和苹果酸含量逐渐下降,D-果糖含量先降后升,其余组分均在贮藏67d时达到释放高峰;货架期间,96d后的货架期非挥发性组分含量均达到高峰。主成分分析结果表明：与出库时相比,冷藏67d后的货架9d时各组分含量均降低,而贮藏后期的货架9d时则升高;冷藏67d时及冷藏96d后的货架期,1-MCP处理均显著降低了糖、酸类物质的峰值,减缓了糖、酸物质的代谢速率,维持了冷藏期间的营养品质并延缓了货架期的品质劣变。偏最小二乘和通径分析结果表明：D-果糖与感官甜酸比呈显著正相关,是主要的直接与间接因子;苹果酸对感官酸度和可溶性固形物(SSC)均有显著正相关性,且对SSC主要通过D -葡萄糖的间接效应来实现;山梨糖醇与pH值呈极显著负相关。     

苹果梨果皮中预存抗菌物质的提取、分离与鉴定

膨大期、采收期、采后100d的苹果梨果皮的乙醇(甲醇)-二氯甲烷粗提取液经TLC分离,以链格孢为指示菌进行生物活性分析均有不同比移值的抑菌带出现,采用气-质联用法(GC/MS)对其成分进一步分析表明,三个时期抑菌带成分存在差异。其中棕榈酸甲酯、油酸甲酯、亚油酸甲酯、鱼鲨烯(三十碳六烯)在膨大期含量最高,随着成熟和衰老的进行,含量逐渐降低,至采后100d,其含量分别为膨大期的1.8%、7.3%、19%和26.6%。推测它们是生长期间苹果梨果皮中存在的主要抗菌物质。邻苯二甲酸酯类是采收期和采后100d果皮中含量相对较高的抗菌物质,其中采后100d检出了6种邻苯二甲酸酯,相对含量高达60%。它们可能为采后果皮中主要的抗菌物质。     

Anthocyanins,Antioxidative, and Antimicrobial Properties of American Cranberry (Vaccinium macrocarpon Ait.) and their Press Cakes

ABSTRACT: Amounts of total phenolics, anthocyanins, and ascorbic acid in 4 American cranberry varieties harvested at 4 stages of maturity were measured. The larger amount of phenolic compounds was found in berries of “Black Veil” cultivar (504 mg/100 g) at II stage of maturity. Significantly larger amounts of anthocyanins were determined in the overripe berries of the cultivars “Ben Lear” and “Black Veil.” The amount of ascorbic acid in berries increased during ripening from I to III stage, and slightly decreased in the overripe berries. The biggest quantities of ascorbic acid were found in the ripe berries of “Ben Lear” cultivar (15.8 mg/100 g). The distribution of anthocyanins pigments was determined by HPLC‐UV/MS in mature berries. The composition of individual anthocyanins in berries was quite similar in all the studied cranberry cultivars. While skins of cranberries are rich in anthocyanins and other phenolic compounds, the extracts of the by‐products of cranberries juice—berry cakes, were analyzed and obtained results were compared with the properties of extracts made from whole berries. The anthocyanins and total phenolics content, radical scavenging activity, antimicrobial activity of the whole berries, and their press cakes extracts were measured. All investigated extracts from berries and their press cakes showed good radical scavenging activity and revealed antimicrobial properties. It was found that Bacillus cereus (ATCC 10876) and Micrococcus luteus (ATCC 9341) were the most sensitive among 10 tested Gram‐negative and Gram‐positive bacteria.     

Sugars and organic acids in Japanese plums (Prunus salicinaLindell) as influenced by maturation, harvest date, storage temperature and period

The effects of fruit maturation, harvest date, storage temperature, storage period and shelf life, on the concentrations of individual sugars and organic acids in Japanese plums were investigated. During fruit maturation in 'Amber Jewel' plums, sucrose concentration increased significantly from 101 days after full bloom (DAFB) to 1 week after commercial maturity (136 DAFB) with a non-significant change in the concentration of total organic acids and malic acid, the major organic acid. The changes in concentrations of sugars and organic acids during cold storage of 'Amber Jewel' plums harvested on 129 and 136 DAFB appeared to be independent of harvest date. Storage of 'Amber Jewel' plums at 5 °C accelerated the loss of sucrose and increased the concentrations of fructose and glucose from the 4^th week of storage compared with those stored at 0 °C. 'Blackamber' plums did not undergo any significant increase in the total and individual sugars during 5 weeks storage and subsequent shelf-life of 8 days at 20 °C. Malic acid concentrations declined during storage from 3 weeks onwards with a further substantial loss during ripening at 20 °C. Maturation, harvest date, storage temperature, storage period and shelf-life affect the concentrations of sugars and organic acids in Japanese plums.     

1-MCP及其结构相似物处理对番茄采后贮藏效果的影响

为了研究环丙烯类乙烯抑制剂的作用效果,以绿熟期番茄为试材,用1-甲基环丙烯(1-MCP)、1-戊基环丙烯(1-PentCP)、1-辛基环丙烯(1-OCP)处理后,常温(18℃±2℃)贮藏,每隔3 d测定1次理化指标,研究三者对番茄果实后熟衰老和贮藏效果的影响。结果表明:1-MCP及其结构相似物处理番茄不同程度地降低了呼吸强度和乙烯释放量的峰值,抑制了番茄果实硬度的下降,延缓了可溶性固形物含量的上升,同时也有效抑制了后熟期番茄果实过氧化氢酶(CAT)活性、过氧化物酶(POD)活性,延缓了果实的后熟衰老。3种试验的抑制剂中,1-MCP、1-PentCP和1-OCP处理随支链长度的增加,抑制后熟衰老的效果依次降低。     

不同模拟流通温度对桃果实硬度和糖酸品质的影响

为了研究常温、冷链、断链3 种流通方式对桃果实品质的影响,在模拟3 种流通方式的温度环境下对桃果实进行贮藏,分析模拟流通过程中的桃果肉硬度、细胞壁果胶和糖酸含量及其组成的变化情况。结果表明,桃果实采后的贮运品质受流通温度的影响显著。模拟常温环境中流通的桃果实在4 d内即失去商品价值;恒定低温的流通条件（模拟冷链流通）可以保证桃果实在贮运期和货架期的良好品质;而模拟断链流通组的桃果实由于在贮藏过程中经历了包装、出入库等环节的温度升高,在进入货架期后果实品质快速下降,货架期第2天的果肉硬度（2.14 g/cm2）、蔗糖含量（46.48 mg/g）和苹果酸含量（3.13 mg/g）显著低于模拟冷链流通组（P＜0.05）。桃果实采后冷链流通过程应尽量避免贮运环节断链造成的温度变化,研究结果可为果蔬冷链流通系统的完善提供参考。     

PHYSIOLOGICAL AND CHEMICAL STUDIES OF CHILLING INJURY IN PEPPER FRUITS

Physiological effects of low temperature (1-6°C) on pepper fruits were studied during and after exposure for various periods. The CO₂ production of the fruits stored at low temperature increased abnormally after transfer to 18°C. There was an accumulation of α-keto acids in chilled fruits: fumaric, succinic, citric and malic acids were detected and malic increased remarkably during low temperature storage. Using paper chromatography, chlorogenic acid was found to be a main phenolic substance in the pepper seeds: its content increased immediately after exposure of the peppers to low temperature and decreased rapidly during subsequent cold storage. The content of shikimic acid in chilled seeds showed a similar tendency to that of chlorogenic acid; phenylala-nine ammonia-lyase (PAL) activity increased rapidly after 2 days' cold storage, then decreased sharply; tyrosine ammonia-lyase (TAL) activity was fairly low compared with PAL activity.     

Effects of 1‐MCP applied postharvest on epicuticular wax of apples (Malus domestica Borkh.) during storage

BACKGROUND: Certain apple cultivars develop a greasy feel when overripe. Treating fruits with the ripening inhibitor 1‐methylcyclopropene (1‐MCP, SmartFresh^™) reduces fruit greasiness. This study examines the nature of this phenomenon. ‘Royal Gala’ apples were treated with 1‐MCP at 1.0 µl L⁻¹ following harvest. Periodically, during storage at − 1 °C for up to 6 months, fruits were evaluated for internal ethylene concentration, fruit epicuticular wax morphology (using scanning electron microscopy) and non‐polar organic solvent‐extractable (NPOSE) wax constituents of the cuticle (using gas chromatography/mass spectrometry). RESULTS: In 2004, 1‐MCP strongly inhibited internal ethylene production; however, total weight of NPOSE wax during storage was unaffected by treatment. In 2005, several wax constituents present in both ‘Autumn Gold’ and ‘Royal Gala’ showed differences during storage. In 2006, cuticular wax constituents comprising 80% of the total from ‘Royal Gala’ showed no treatment differences. Although several minor constituents did exhibit differences within treatment and sampling date, these did not appear sufficient to cause the subtle differences in surface wax morphology. CONCLUSION: 1‐MCP strongly inhibited ethylene production and delayed development of certain wax constituents thought responsible for fruit greasiness during cold storage. Subtle differences in surface wax morphology appeared unrelated to wax production. Published in 2008 by John Wiley & Sons, Ltd.     

Assimilate transport in grapevines -effect of phloem disruption

Assimilate translocation in mature grapevines (cv. Gewürztraminer and cv. Harslevelü) under field conditions was investigated during the growth season by quantifying individual sugars and organic acids in mature leaves, shoot bark and berries, as affected by girdling the shoot just above the bunches. Tissue was sampled at berry set, pea size, veraison and ripeness stages of the vine. Invertase activity was determined in the shoot bark at ripeness. In the leaves, malic acid concentrations reached lowest levels at pea size, but increased thereafter. Tartaric acid decreased after peaking at pea size stage. Tartaric acid concentrations increased with girdling. Despite the increase in leaf age, sucrose concentrations remained virtually stable during the season, emphasising the importance of mature leaves for nourishing bunches. Girdling resulted in a build‐up of sucrose in the leaves. In the bark, malic and tartaric acid stayed more or less the same during the growth period, but increased above the girdle. As a result of phloem disruption, sucrose also increased. The increase in glucose and tartaric acid is believed to result from catabolic cleavage of sucrose by invertase. Invertase activity was evident in the bark (of mature Harslevelü vines) at ripeness, which may indicate involvement in osmotic adjustments and gradients in the bark/phloem structure. In the berries, malic and tartaric acids reached peak concentrations at pea size. The volume increase during the ripening period, and in the case of malic acid also respiratory loss, resulted in a decrease in organic acid concentration. Malic acid continued to decrease after the initial decline, whereas tartaric acid stayed virtually stable. Girdling had no marked effect on organic acid accumulation in the berries. Sucrose concentrations were low during the first part of the season, but increased thereafter. Sucrose concentrations during ripening increased with girdling, which may represent a concentration effect and/or import from the rest of the vine. Sucrose concentrations (in mature Harslevelü vines) were indeed lower below than above the girdle. Comparison of sucrose concentrations in the leaves, bark and berries showed the existence of a decreasing concentration gradient, in line with the source:sink transport concept. An equally prominent decrease in sucrose:glucose ratio in the berries from the start of the ripening period indicates that vacuolar integrity (compartmentation) was affected in the ripening berry, most probably allowing hydrolysis of sucrose by invertase and decreasing osmotic potential within the berry. The results provide further evidence for the hypothesis of an osmotic gradient driven transport to the berry.     

1-MCP对净皮甜石榴的冷藏保鲜效果

对陕西临潼净皮甜石榴采后用不同浓度(0.25、0.5、1.0、1.5μL/L)1-MCP处理后于4℃冷藏,定期测定了部分采后生理指标并统计果实的腐烂情况。结果表明,1-MCP处理能维持果实相对较高水平的有机酸含量、出汁率和花青苷含量,抑制了石榴果皮相对电导率的上升速率,降低了石榴的乙烯释放速率,从而延缓果实的衰老,有效降低了冷藏期和货架期石榴的腐烂率与腐烂指数。在0.25～1.5μL/L的1-MCP浓度范围内,处理浓度越低,果实品质和保鲜效果越好。     

The effects of fruit maturation,delayed storage and ethylene treatment on the incidence of low‐temperature breakdown of ‘Hayward’ kiwifruit

BACKGROUND: Low‐temperature breakdown (LTB), a disorder inducing quality loss, during and after cold storage of ‘Hayward’ kiwifruit was investigated. Harvested kiwifruits during fruit maturation or after delayed storage (DS) at 20 °C for 0, 1, 2, 3 and 4 weeks and 1 µL L^?1 ethylene treatment for 24 h were stored at ? 0.5 °C for 24 weeks and additional ripening at 20 °C for 5 days. Fruit quality indices and LTB incidence and severity were determined before and after treatments. RESULTS: Harvested fruits ripened during maturation, DS and after ethylene treatment. After storage and shelf life, fruits of all treatments were at complete ripening stage. LTB incidence of early harvested fruits was high, while that of fruits of the mid (third) and late harvests was low. Fruits of the third harvest date showed progressively increased LTB incidence with increasing duration of DS to as high as 95–100% after 4 weeks. Ethylene‐treated fruits showed a comparable increase in LTB to that corresponding to 2–3 weeks of DS. CONCLUSION: In contrast to fruit maturation, postharvest (after harvest and before storage) DS at non‐chilling temperature and ethylene treatment advanced the ripening of ‘Hayward’ kiwifruit and resulted in increased LTB incidence. Copyright © 2012 Society of Chemical Industry     

THE NONVOLATILE ACID AND SUGAR COMPOSITION OF MAYHAW FRUITS (CRATAEGUS AESTIVALIS, C. OPACA, C. RUFULA)

Nonvolatile acid and sugar compositions were determined in ten cultivars from three species of mayhaw fruits (Crataegus aestivalis, Walter, Torrey & Gray; C. opaca, Hook. & Arn.; C. rufula, Sarg.). Fructose and glucose were the major sugars and malic acid was the principle nonvolatile acid found in these fruits. Citric acid, quinic acid, sorbitol, sucrose, xylose, and inositol were quantitated but were found in lesser amounts and succinic acid, arabinose, and galactose were trace components in all fruits. Pyruvic acid and tartaric acid were tentatively identified in most cultivars based on GC retention times. The nonvolatile acid and sugar composition among all mayhaw fruit species were very similar although one unnamed cultivar of C. aestivalis had much higher levels of fructose and glucose, and the cv. T. O. Superberry had higher levels of malic acid. Malic acid levels were found to be much higher in mayhaw fruits than the levels reported in other stone and pome fruits. Three cultivars of C. rufula grown under cultivation yielded mature fruit with almost identical nonvolatile acid and sugar composition.     

Low oxygen treatment prior to cold storage decreases the incidence of bitter pit in ‘Golden Reinders’ apples

BACKGROUND: The effect of subjecting ‘Golden Reinders’ apples to a low O₂ pre‐treatment (LOT; 1–2% O₂) was evaluated as a strategy to decrease the rate of bitter pit (BP) incidence after standard cold storage (ST). Immediately after harvest, apples were stored for 10 days at 20 °C under low O₂. Thereafter, apples were cold‐stored (0–4 °C) for 4 months and changes were monitored in terms of BP incidence, fruit quality traits and mineral element concentrations. RESULTS: After 4 months cold storage, LOT apples presented a 2.6‐fold decrease in the rate of BP incidence (14%) versus the values obtained for standard cold‐stored fruits (37% BP incidence). LOT increased flesh firmness, total soluble solids and titratable acidity as compared to the quality traits determined for cold‐stored fruits. Lower cortex Ca and Mg concentrations as compared to ST apples were determined in association with LOT, 2 months after cold storage. CONCLUSION: Application of a LOT prior to cold storage may be a promising strategy to reduce the incidence of BP and preserve fruit quality, which should be further investigated. Copyright © 2009 Society of Chemical Industry     

Physiological and biochemical response of harvested plum fruit to oxalic acid during ripening or shelf-life

The effect of oxalic acid application on plum fruit (Prunus salicina cv. ‘Damili’) ripening properties during storage or shelf-life was determined. The fruits were dipped for 3 min in solutions containing 5 mmol/L oxalic acid and then were packed into polyethylene bags and stored at 25 °C for 12 days, or at 2 °C for 20 days and subsequently at 25 °C for 12 days. Ethylene production, fruit firmness, contents of pectin and anthocyanin, specific activities of polygalacturonase (PG), pectin methylesterase (PME) and phenylalanine ammonia lyase (PAL), and chlorophyll fluorescence (Fv/Fm) were measured. The application of oxalic acid reduced ethylene production and delayed softening of plum fruit. The inhibition of softening was associated with decreased PG and PME activities; that is, the retardation of pectin solubilization/degradation. During storage or shelf-life, flesh reddening and anthocyanin synthesis were significantly inhibited in oxalic acid-treated plum fruit, accompanied with decreased PAL activity. Furthermore, it was found that variable:maximalchlorophyll fluorescence (Fv/Fm), an indicator of ripening, senescence or stress injury of fruit and vegetable, decreased much more slowly in oxalic-treated plum fruits than in control fruits. Thus, oxalic acid treatment can be an effective means to extend the shelf life of plum fruit.     

Changes in Free Amino Acid and Total Nitrogen Concentrations During Maturation of Muscadine Grapes (V. rotundifolia)

Free amino acids, ammonia and total nitrogen were followed during maturation of berries of Carlos and Noble muscadine grapes (V. rotundifolia). Chemical analysis was done on deseeded berries. Ammonia decreased in the berries of both cultivars during maturation. Total nitrogen content fluctuated and was not significantly correlated with maturity in either cultivar. Threonine (THR) and histidine + gamma aminobutyric acid (HIS + GABA) were the predominant free amino acids in both cultivars at an immature berry stage. At full berry maturity, arginine (ARG) was the predominant amino acid in Carlos, having increased over 100-fold during the sampling period while ARG, alanine (ALA), THR, and HIS + GABA accounted for 72.3% of the total free amino acids. ALA was the predominant free amino acid in mature berries of Noble and accounted for 30.4% of the total free amino acids. Of the additional cultivars sampled only at their normal harvest date, berries of Pride, Magnolia and Regale contained nearly equal amounts of ARG and ALA as the predominant amino acids. Mature Dixie berries had twice as much ALA (29.8%) as ARG (12.8%). In general, the free amino acids in berries of muscadine grapes were found in concentrations similar to those reported in the literature for V. vinifera and V. labrusca cultivars. However, the large increase in proline concentration reported to occur during maturation of berries of V. vinifera cultivars was not found in any of the muscadine cultivars examined.     

外源L-Arg处理对蜜橘果实贮藏品质的影响

用100、200 μmol/L外源L-精氨酸（L-arginine,L-Arg）溶液浸泡处理蜜橘果实10 min,探讨该处理对采后蜜橘果实贮藏品质的影响。结果表明,适宜浓度（200 μmol/L）的外源L-Arg处理可以有效抑制蜜橘果实黄化,在一定程度上抑制果皮细胞膜透性的增加;在贮藏的前28 d内,L-Arg浸泡处理能够维持果实可溶性固形物的含量;各处理组之间的呼吸速率没有显著性差异,适宜浓度（200 μmol/L L-Arg）的L-Arg浸泡处理能够在一定程度上抑制蜜橘果实质量损失率的增加;延缓果实总酚、抗坏血酸含量的减少,贮藏前期（0～21 d）处理组果实果肉类黄酮含量与对照组之间无显著差异,贮藏后期（28～35 d）处理组果实类黄酮含量显著低于对照组果实。即200 μmol/L外源L-Arg处理能够在一定程度上有效延缓采后蜜橘果实的衰老和品质下降。     

Composite starch‐based coatings applied to strawberries (Fragaria ananassa)

Starch‐based coatings were used to the extend storage life of strawberries (Fragaria ananassa) stored at 0°C and 84.8% relative humidity. Effects of coating formulation (including starch type, plasticizer, lipid and antimicrobial agent) were analysed with respect to fruit quality. Plasticizer addition was necessary for film and coating integrity to avoid pores and cracks. Plasticizer presence reduced weight losses and maintained surface colour of fruits. Amylomaize coatings showed lower water vapour and gas permeabilities and decreased weight losses for longer periods than corn starch ones. Coatings with sorbitol showed lower permeabilities than glycerol ones. Coatings with antimicrobial agents decreased microbial counts, extending storage life of coated fruits by 10 to 14 days in comparison to the control. The addition of 2 g/l sunflower oil to the formulations decreased the water vapour permeability of starch‐based films, maintained the surface colour of coated fruits and controlled effectively fruit weight losses during storage. Lipid addition minimized the effects of starch and plasticizer types. Composite starch‐based coatings showed selective gas permeability (CO₂ higher than O₂) which helps to delay senescence of fruits.     

ETHYLENE CAPSULE PROMOTES EARLY RIPENING OF 'd'ANJOU' PEARS PACKED IN MODIFIED ATMOSPHERE BAGS

‘d'Anjou’ pears (Pyrus communis, L.) harvested commercially with flesh firmness of 64.5 N were incapable of ripening normally at 20C within 60 days of air storage at ‐1C (denoted as “under‐chilled” fruits). When under‐chilled ‘d'Anjou’ fruits (8 fruits, total fruit weight of 1.8 kg) were packed in a 3.8‐liter perforated bag inserted with an ethylene capsule, fruit would ripen normally at 20C. The ethylene concentration in the packed bag maintained no less than 100 ppm after 4 days at 20C, and declined to about 25 ppm on day 7. Regardless of the storage length, ripened fruit induced by the ethylene capsule developed high buttery and juicy texture. If ‘d’ Anjou’ fruit had been stored at ‐1C for less than 30 days, ripened fruit lacked high flavor quality. Flavor quality of ripened fruit improved rapidly when the fruit had been stored for longer than 30 days.     

不同浓度1-MCP和1-OCP处理对青熟期芒果后熟和衰老的影响

研究了不同浓度(1、5和50μl/L)的环丙烯类乙烯效应抑制剂1-MCP(1-甲基环丙烯)和1-OCP(1-辛基环丙烯)常温[(20±2)℃]熏蒸处理20h对青熟期芒果(Mangifera indica L.)后熟和衰老的影响。结果表明:不同浓度的环丙烯类乙烯效应抑制剂均能不同程度地延缓芒果果实可滴定酸、MDA(丙二醛)含量的下降;降低POD(过氧化物酶)、PPO(多酚氧化酶)活性;抑制硬度的下降和SSC(可溶性固形物)含量的上升;减缓果实质量损失和成熟度的进程;呼吸高峰出现的时间与对照相比延迟了3 d。表明1-MCP和1-OCP处理能有效地延缓芒果果实的后熟和衰老,其中以5μl/L 1-MCP和50μl/L 1-OCP的效果较佳。