基于代谢组学分析黑老虎果实营养成分及不同部位富集差异

近年来，中药材黑老虎的果实被作为一种新型水果而广受关注，为深入了解其营养价值，利用广泛靶向代谢组学技术检测代谢物，分析其中的营养成分及在果皮、果肉、种子的富集格局。结果显示，在黑老虎果实中鉴定出429个营养成分，其中果皮中有424个、果肉中429个、种子中391个，3个部位共有的为389个；氨基酸及其衍生物数量最多(占22.6%),其余主要为有机酸(18.6%)、游离脂肪酸(13.5%)、糖及醇类(12.8%)、核苷酸及其衍生物(11.2%)。果皮和种子营养物质丰度相当，但都明显低于果肉，其主要原因为有机酸、游离脂肪酸、溶血磷脂酰乙醇胺在果肉中显著向上表达。黑老虎果皮、果肉和种子有大量相同营养成分，可连同开发利用；3个部位都分别含有多种高度富集的营养成分，在食品和药用领域开发利用价值较大。     

高原雪菊与平原雪菊中黄酮类成分及其关键酶基因表达的差异分析

为了分析比较高原雪菊与平原雪菊类黄酮化合物成分差异，采用超高液相色谱-串联四级杆飞行时间质谱（UPLC-QTOF-MS）技术对雪菊头状花序的类黄酮化合物进行定性定量分析。依据UPLC-QTOF-MS 矩阵中的保留时间、质荷比及碎片离子对雪菊中的黄酮类代谢产物进行分析鉴定，比较高原雪菊与平原雪菊代谢产物的相对含量。结果表明，从昆仑雪菊中共分析鉴定出204个黄酮类成分，PCA 分析结果显示两个产地样本的黄酮类化合物差异明显，通过 OPLS-DA 筛选出4,4""-二甲氧基查耳酮、棕矢车菊素、7,4""-二羟基黄酮和槲皮素等15种差异表达的黄酮类代谢物，其中6种黄酮类化合物在平原雪菊中含量较高，9种黄酮类化合物在高原雪菊中含量较高。通过对差异代谢物通路分析，发现类黄酮生物合成（Flavonoid biosynthesis）、次生代谢物的生物合成（Biosynthesis of secondary metabolites）、黄酮和黄酮醇生物合成（Flavone and flavonol biosynthesis）、代谢途径（Metabolic pathways）、异黄酮生物合成（Isoflavonoid biosynthesis）和苯丙酸类化合物的生物合成（Biosynthesis of phenylpropanoids）等6条代谢途径显著差异。结论：昆仑雪菊的黄酮类化合物种类多样且含量丰富，其含量丰富的黄酮类化合物可能是昆仑雪菊具有显著药用价值的物质基础，且不同产地雪菊含有特有的黄酮类成分，可通过检测特定的黄酮类化合物进行雪菊产地的鉴定。     

中国野生刺葡萄（Vitis davidii Foex）及其单品种葡萄酒中花旗松素含量分析

利用高效液相色谱-串联质谱联用技术对原产中国的野生刺葡萄果实的果皮、果肉、种子及单品种葡萄酒中的花旗松素含量（以鲜质量计算）进行测定与分析。结果表明：刺葡萄果实果皮中花旗松素含量最高,其含量在刺葡萄黑、白果实中分别为（2.44±0.18）、（2.03±0.14） mg/kg,在种子中分别为（1.66±0.13）、（1.38±0.12） mg/kg,果肉中含量最低,分别为（0.36±0.02）、（0.25±0.02） mg/kg。刺葡萄黑、白果实中各个部位花旗松素含量均无明显差异,但对照品种黑色果实果皮中的花旗松素含量显著高于白色果实,这说明花旗松素含量的高低与葡萄果皮颜色并无直接关系。在单品种酒中,白葡萄酒由于酿造工艺不同,果皮和种子中的花旗松素无法进入酒中,花旗松素含量仅为红葡萄酒的20%;葡萄酒中的花旗松素含量略低于果实是因为提取果实中花旗松素的溶剂是甲醇,而葡萄酒中只是水和乙醇的自然浸渍。     

基于广泛代谢组学的荔枝果肉营养代谢物综合解析

采用基于超高效液相色谱-电喷雾四极杆飞行时间串联质谱法多反应监测模式的广泛靶向代谢组学对10个荔枝品种的果肉中539种代谢物进行鉴定,描述关于荔枝代谢物组成和丰度的全面信息。结果表明：荔枝果肉初生代谢物298个（55.29%）,次生代谢物228个（42.30%）;其中氨基酸及其衍生物（82个,15.21%）、脂质（60个,11.13%）、有机酸（59个,10.95%）、核苷酸及其衍生物（53个,9.83%）、糖类及醇类（25个,4.64%）是主要的初生代谢物,黄酮（129个,23.93%）、酚酸类（54个,10.02%）、生物碱（31个,5.75%）是主要的次生代谢物。采用主成分分析和聚类热图分析系统地比较10个荔枝品种的代谢物,发现不同品种间存在明显的分组模式,共聚类为3组且与品种之间的熟期及风味品质相对应。同时关注每类成分中相对含量大于1%的最重要的代谢物,揭示了各类代谢物对荔枝果肉营养的贡献,发现了γ-氨基丁酸、肌醇、石榴酸、葫芦巴碱几种丰度较高且具有特殊功效和营养的代谢物。鉴于荔枝的代谢产物鉴定与人们的营养与健康、果实风味及抗性有着密切的关系,本实验将为鲜食营养、栽培育种、综合...     

基于超高效液相色谱-四极杆-飞行时间高分辨质谱分析酸橙果实中的生物活性成分

应用超高效液相色谱-四极杆-飞行时间高分辨质谱结合靶向和非靶向筛查方法系统分析鉴定了6个酸橙果实品种的不同部位(果皮、果肉、果汁)的生物活性物质。根据化合物的精确分子质量、质谱裂解规律、碎片离子信息,结合数据库匹配、标准品比对并参考相关文献对化合物结构进行鉴定。该实验共鉴定了84种生物活性成分,包括44种类黄酮、8种酚酸、22种香豆素、2种类柠檬苦素、8种生物碱,其中35种生物活性成分首次在酸橙中报道,进一步丰富了酸橙生物活性成分的数据库。小叶酸橙、代代酸橙、万木橙、蚌柑、摩洛哥酸橙和黄皮酸橙分别筛查鉴定出72、71、68、71、71和66种生物活性成分。通过层次聚类分析发现6个酸橙品种以及果实不同部位生物活性物质代谢模式具有一定的差异,代代酸橙和蚌柑积累模式相近,小叶酸橙、万木橙、摩洛哥酸橙和黄皮酸橙之间差异较大。不同部位鉴定的生物活性成分数量呈以下规律：果皮≥果肉≥果汁。该研究结果可为酸橙的质量评价和药效物质基础研究提供实验依据,并为其后续的资源开发奠定基础。     

火龙果果实甜菜苷类色素组成与分布

目的：明确火龙果果实中甜菜苷类色素（BLs）组分构成及其部位归属。方法：采用超高效液相色谱飞行时间质谱法对3类火龙果果实\[红皮红肉型（RR）、红皮白肉型（RW）和黄皮白肉型（YW）\]的果肉部位和果皮部位甜菜苷类色素（BLs）进行筛查和结构确证。结果：3类火龙果果实中共鉴定出甜菜苷、丙二酰甜菜苷和梨果仙人掌黄质等19种组分,RR火龙果的果皮部位鉴定的BLs组分最多（14种）,其次是RR果肉部位（12种）及RW果皮部位（9种）。结论：RR火龙果果实BLs组分最为丰富,RW次之,YW最少;BLs主要分布在红色果肉和红色果皮部位,在白色果肉和黄色果皮部位则较少。果肉、果皮部位检测出BLs组分分别为12,16种。     

超高效液相色谱-四极杆-飞行时间高分辨质谱法快速筛查柠檬果实中的生物活性成分

基于前期实验室构建的生物活性成分质谱数据库,该文建立了同时筛查并准确鉴定类黄酮、香豆素、酚酸、生物碱及类柠檬苦素多类型生物活性成分的超高效液相色谱-四极杆-飞行时间高分辨质谱方法,可快速、准确筛查6种柠檬不同部位(果皮、果肉与果汁)的生物活性成分,结果表明,在6种柠檬样品中共鉴定出40种类黄酮、27种香豆素、9种酚酸、7种生物碱和3种类柠檬苦素。扁红柠檬、北京柠檬、柯尔提粗柠檬、尤力克柠檬、里斯本柠檬和美国粗柠檬分别筛查鉴定出72、71、70、66、64和63种生物活性成分。不同部位鉴定的生物活性成分数量呈以下规律:果皮≥果肉≥果汁。该方法经过实际样品验证,并可广泛适用于柑橘类水果中生物活性成分筛查分析鉴定。     

4种柠檬不同组织的酚类物质分布及其抗氧化特性

采用分光光度计法评价4种柠檬(尤力克黄柠檬、小青柠、青柠檬、香水柠檬)中果皮与果肉的总酚含量与抗氧化活性(清除ABTS+自由基能力、铁离子还原能力和清除DPPH自由基能力),并用超高效液相色谱对其酚类物质进行定性和定量。结果表明:4种柠檬果皮中的总酚含量及抗氧化活性均显著高于果肉(P0.05),其中尤力克果皮与果肉的总酚、抗氧化活性均显著高于其余3个品种(P0.05),而香水柠檬果皮与果肉中总酚、清除ABTS+自由基能力均最低。不同品种柠檬中酚酸、类黄酮种类及含量差异较大。从4种柠檬中共检出21种酚类物质,其中酚酸6种,黄酮6种,黄烷酮6种,多甲氧基黄酮3种。柠檬中的酚类物质主要是黄烷酮,占类黄酮总量61.82%～91.61%,其中青柠檬果皮中酚酸总量最高(535.62 mg/100 g DW),尤力克果皮中类黄酮总量最高(1 506.33 mg/100 g DW),果肉规律与果皮基本一致,然而其含量显著低于果皮含量(P0.05)。从尤力克果皮与果肉中共检出15种酚类物质,其中圣草枸橼含量最高,而新绿原酸是含量最高的酚酸。从小青柠、青柠檬和香水柠檬的果皮与果肉中分别检测出19,16,15种酚类物质,其中橙皮苷含量均最高,而香草酸是含量最高的酚酸。不同品种柠檬的总酚和总类黄酮含量与ABTS+呈极显著的正相关性,同时总酚含量与DPPH呈显著性的正相关性。     

基于超高效液相色谱-四极杆-飞行时间高分辨质谱分析酸橙果实中的生物活性成分

应用超高效液相色谱-四极杆-飞行时间高分辨质谱结合靶向和非靶向筛查方法系统分析鉴定了6个酸橙果实品种的不同部位(果皮、果肉、果汁)的生物活性物质.根据化合物的精确分子质量、质谱裂解规律、碎片离子信息,结合数据库匹配、标准品比对并参考相关文献对化合物结构进行鉴定.该实验共鉴定了84种生物活性成分,包括44种类黄酮、8种酚...     

黑老虎聚合果的主要营养活性成分分析

以黑老虎“湘黑-0701”聚合果为材料,分别研究其果皮、果肉果汁、种子和果芯4部分主要营养活性成分。结果表明：聚合果中果皮占比（42.52%~47.75%）最大,果肉果汁占比（35.23%~37.77%）次之。黑老虎种子在聚合果中占比（7.55%~11.26%）小,但灰分（7.25%）、蛋白质（11.24%）、粗脂肪（22.20%）均为最高,且富含多种矿质元素尤其锰（90.573 mg/kg）、锌（9.675 mg/kg）含量丰富;种子中的不饱和脂肪酸含量高达74.78%,其中C18:2（亚油酸）高达60.30%;组成也较为丰富;种子中的游离多酚（23.69 mg/g）、结合酚（6.90 mg/g）、总多酚（30.59 mg/g）和总黄酮（30.54 mg/g）含量最高。本研究表明黑老虎种子是一个特别应该引起重视的健康食品原料;果皮皮厚（1.11~2.59 mm）、生物碱（3.20 mg/g）和花色苷（8.89 mg/g）含量高,宜从功能果脯蜜饯的角度去开发;而果肉果汁则可从特色饮料角度去开发。种子灰分、蛋白质、粗脂肪含量高,则可从油脂、功能产品方面去开发。     

Identification and quantification of phenolic and other polar compounds in the edible part of Annona cherimola and its by-products by HPLC-DAD-ESI-QTOF-MS

Annona cherimola fruit is native to inter-Andean valleys from Peru and Ecuador. In the Mediterranean region, the main producer of cherimoya is the coast of Granada–Malaga (Spain), also called ‘Costa Tropical’, where the two most important cultivars found are ‘Fino de Jete’ and ‘Campa’.Cherimoya, like most fruits, is an important source of bioactive compounds, such as phenolic compounds. Therefore, the aim of this study was the tentative identification and quantification of phenolic and organic acids in pulp, peel and seed of two cherimoya cultivars (‘Fino de Jete’ and ‘Campa’) using HPLC-DAD-ESI-QTOF-MS.By using the proposed method, 21 phenolic and organic acids were detected in the edible portion of cherimoya, 37 in peel and 22 in seed. Procyanidins were the main phenolic compound family identified in the pulp and peel of the two cultivars, whereas in cherimoya seeds higher quantities of organic acids and flavonoids were detected. Most of the compounds were identified for the first time in cherimoya.According to these results, cherimoya pulp and its by-products are a natural source of procyanidins and other phenolic and polar compounds. In particular, cherimoya peel, with a higher concentration of phenolic and polar compounds in comparison with pulp and seed, represents an interesting food by-product that could be used as an ingredient in the functional food and/or pharmaceutical industry.     

Characterization of phenolics by LC-UV/vis, LC-MS/MS and sugars by GC in Melicoccus bijugatus Jacq. 'Montgomery' fruits

Fruits of the native South American tree Melicoccus bijugatus Jacq. (Sapindaceae) are consumed for both dietary and medicinal purposes, but limited information is available about the phytochemistry and health value of M. bijugatus fruits. Fruit tissues of the Florida Montgomery cultivar were assessed for sugars, using gas chromatography, and for total phenolics, using UV spectroscopy. Reverse phase high performance liquid chromatography (HPLC) fingerprints of crude methanolic pulp, embryo and seed coat extracts were obtained at 280 nm. Phenolics were characterised by both HPLC UV/vis analysis and HPLC electrospray ionization tandem mass spectrometry. Major sugars detected in the pulp and embryo extracts were sucrose, followed by glucose and fructose. The glucose:fructose ratio was 1:1 in the pulp and 0.1:1 in the embryo. Total phenolic concentrations of the fruit tissues were in the order: seed coat > embryo > pulp. Phenolic acids were identified mostly in pulp tissues. Phenolic acids, flavonoids, procyanidins and catechins were identified in embryo tissues, and higher molecular weight procyanidins were identified in seed coat tissues. This study provides new information about the phytochemistry and the potential health value of the Montgomery cultivar M. bijugatus fruit tissues.     

Analysis of phenolic compounds including tannins,gallotannins and flavanols of Uapaca kirkiana fruit

Tannins and phenolic acids were extracted from Uapaca kirkiana unripe pulp, seed coat, peel and embryo, as well as from ripe pulp, seed coat, embryo and peel portions of the fruit. Extraction was done using 50% methanol. More tannins were detected in the embryos of both ripe and raw fruit. Both ripe and raw seed coat contained the least amounts of tannins. The flavanoids and gallotannins also followed the same trend, with most of them in the embryos of both, the ripe and raw, fruit portions whilst the least were found in the seed coat. Tannins were, however lost during sun-drying compared to oven-drying, even though the differences were not very large. Also, raw fruits showed high concentrations of tannins compared to the ripe fruits. Hydroxybenzoic acid was found in the peel and pulp but none was detected in the seed coat or in the embryo. Similar phenolic acids were detected in the seed coat, except for caffeic acid and protocatechuic acid, detected in the embryo by both the UV florescence and Folin spray.     

八月瓜果实营养成分分析和评价

为分析研究八月瓜果实的营养价值,本文用火焰原子吸收光谱法、液相色谱法、荧光分光光度法等实验方法对八月瓜果皮、果肉和种子中营养物质成分进行检测分析。基于检测分析可知,八月瓜果实具有很高的营养价值。其中,八月瓜果皮含有锰、钾矿物质营养成分,含量分别为0.645、342 mg/100 g;八月瓜果皮总氨基酸含量为0.313 mg/100 g,含15种氨基酸,其中必需氨基酸7种,必需氨基酸比重达到WHO/FAO提出理想蛋白质条件,必需氨基酸含量不及果肉均衡,营养价值比果肉低;含有少量的维生素E、果胶、蛋白质和脂肪。八月瓜种子含有多种矿物质营养成分,即含钾、磷、钙、铁矿物质营养成分,含量分别为586、180、191、2.85 mg/100 g;八月瓜种子富含多种矿物质营养成分,即富含锰、铜、镁矿物质营养成分,含量分别为:4.63、1.3、157 mg/100 g;脂肪酸含量为2.662 g/100 g,不饱和酸含量比重为76%。八月瓜果肉含有铜矿质营养成分,含量为0.25 mg/100 g;富含锰矿物质营养成分,含量为7.51 mg/100 g;八月瓜果肉总氨基酸量含量为0.419 mg/100 g,含16种氨基酸,其中必需氨基酸8种,必需氨基酸比重达到WHO/FAO提出理想蛋白质条件,必需氨基酸含量均衡,营养价值高;含有少量的维生素、脂肪、蛋白质和黄酮。本文可为八月瓜果的开发利用提供理论支持和技术指导,推动八月瓜理论研究进程。     

Fatty acids,tocopherols, phenolic and antioxidant properties of six citrus fruit species: a comparative study

Citrus fruit is a rich source of bioactive phytochemicals. Information on the fatty acid and tocopherol composition of locally grown citrus fruits in Korea is elusive. This work was aimed to study fatty acid, tocopherols, ascorbic acid, antioxidant potential, and selected phenolics from peel and pulp of six citrus species. The most dominant fatty acid was linoleic acid (15–45%), followed by linolenic, palmitic, and oleic acid. Stearic acid was highly abundant in yuzu peel (14.45%) and pulp (15.88%) compared to the other fruits. Unsaturated fatty acids (54–74%) contributed higher composition than saturated fatty acids (25–46%). Peel exhibited better antioxidant potential and contained higher phytochemicals than pulp. The concentrations of α-tocopherol and γ-tocopherol were ranged from 22.96 (yuzu) to 86.93 (cheonhyeyang) and 38.59 (yuzu) ~83.03 (tangerine) μg/g DW, respectively. J-Redhyeyang peel exhibited highest total flavonoids (4.17?±?0.10 mgQE/g DW) and DPPH radical scavenging activity (6.17?±?0.03 mgTE/g DW). FRAP values were highest (20.05?±?0.64 mgTE/g DW) in yuzu peel, while peel of cheonhyeyang was superior in total phenolic contents. Tangerine (3.02?±?0.05 mg/g DW) and yuzu (7.49?±?0.38 mg/g DW) had higher hesperidin concentrations in pulp and peel, respectively. Naringin was found in an appreciable amount in yuzu pulp (2.04?±?0.09 mg/g DW) and peel (6.30?±?0.19 mg/g DW) but not detected in all other fruit species. Our results indicate that citrus fruit peel is the rich source of antioxidant compounds, which can be used to prepare antioxidant rich food product.     

Phytochemicals and antioxidant activity of different fruit fractions (peel,pulp, aril and seed) of Thai gac (Momordica cochinchinensis Spreng)

Three fractions (peel, pulp and aril) of gac fruit (Momordica cochinchinensis Spreng) were investigated for their phytochemicals (lycopene, beta-carotene, lutein and phenolic compounds) and their antioxidant activity. The results showed that the aril had the highest contents for both lycopene and beta-carotene, whilst peel (yellow) contained the highest amount of lutein. Two major phenolic acid groups: hydroxybenzoic acids and hydroxycinnamic were identified and quantified. Gallic acid and p-hydroxybenzoic acid were found in all fractions. Ferulic acid and p-hydroxybenzoic acid were most evident in pulp. Myricetin was the only flavonoid found in all fractions. Apigenin was the most predominant flavonoid in pulp (red), whereas rutin and luteolin gave the highest content in aril. The extracts of different fractions exhibited different levels of antioxidant activity in the systems tested. The aril extract showed the highest FRAP value. The greatest antioxidant activities of peel and pulp extracts were at immature stage, whereas those in the seed extracts increased from mature stage to ripe stage. The contents of total phenolic and total flavonoid in peel and pulp decreased during the fruit development stage (immature > ripe fruit) and subsequently displayed lower antioxidant capacity, except for the seed.     

不同晚熟柑橘中酚类物质的含量检测及分析

采用超高效液相色谱(ultra-performance liquid chromatography,UPLC)对9种晚熟柑橘(沃柑、春见、大雅柑、不知火、默科特、红肉脐橙、伦晚脐橙、红翠2号和塔罗科血橙)中的主要酚类物质(13种类黄酮和7种酚酸)进行测定,分析比较不同品种柑橘果皮、果肉和果汁(柑橘原汁)中酚类物质种类和含量的差异。结果表明:9个柑橘品种的果皮、果肉、果汁中,类黄酮均以橙皮苷为主,酚酸以阿魏酸为主,且果皮中多甲氧基黄酮含量丰富。在9个柑橘品种果汁中,春见的橙皮苷、咖啡酸含量最高。果肉中,沃柑中阿魏酸、咖啡酸、芥子酸含量最高,塔罗科血橙的橙皮苷、对香豆酸含量最高。果皮中,默科特的芸香柚皮苷、川皮苷、阿魏酸含量最高。杂柑果皮中咖啡酸、阿魏酸及川皮苷含量高于橙类。晚熟柑橘含有丰富的酚类物质,并呈现显著的多样性。     

LC–DAD–MS (ESI+) analysis of the phenolic content of Sorbus domestica fruits in relation to their maturity stage

The aim of this study was the detailed qualitative and quantitative analysis of the phenolic content of several extracts and fractions of Sorbus domestica fruits. The analysis was realized by LC–DAD–MS (ESI+). Twenty-four different extracts and fractions of five different maturity stages of the fruit were analyzed for comparison reasons in order to determine the most beneficial for health type of consuming. Sixty-two different phenolics were identified. There were significant qualitative and quantitative differentiations in the phenolic content among the different types of the fruits. All categories were rich in benzoic, phenylpropanoic and cinnamoylquinic acids and derivatives. Unripe fruit categories were also rich in flavonoids, while well matured fruit categories had a low content of flavonoids. Fruit pulp, which was proved to be a strong antioxidant according to previous research work, contained very low amounts of both acids and flavonoids, but its phenolic content was highly qualitatively differentiated from the other categories.     

Comparison of the polyphenol profiles of apple fruit cultivars by correspondence analysis

Concentrations of the major flavonoids and phenolic acids in the peel and cortex of fruit of eight commercial apple cultivars were determined by HPLC. The multivariate statistical technique of correspondence analysis was applied to the polyphenol profiles to describe distinctive groups of cultivars and of polyphenols, and their joint correspondences. Cultural and growing conditions had a limited effect on the polyphenol profiles of the cortex and peel. Chlorogenic acid was the principal polyphenol in the cortex with the lowest levels being in Red Delicious and the highest in Jerseymac, which were compensated by changes in phlorizin. Cortland had low levels of chlorogenic acid and Gravenstein had high levels, but these were offset by the levels of catechins. The quercetin, rhamnoside, was the principal phenolic compound for the peel data with low levels in Red Delicious, Cortland, Spartan and Jerseymac and high levels in Golden Delicious, Gravenstein and Northern Spy. Levels of chlorogenic acid, offset by levels of phlorizin and catechins, distinguished between Red Delicious and Cortland. Rutin was important in distinguishing between Jerseymac and Spartan.     

Impact of shelf life on content of primary and secondary metabolites in apple (Malus domestica Borkh.)

In this study, we evaluated the changes in apple fruit quality during shelf life. After a month of cold storage, apples of cultivars "Jonagold" and "Golden Delicious" were exposed to ambient temperatures for 21 d, with subsequent sampling every 3 or 4 d. Fruit firmness, changes in amounts of sugars, malic acid, and phenolics were observed during shelf life. Chemical analyses were done with HPLC-PDA system. An interchange between various sugars was noticed, but in general, the sum of sugars remained at the same level. The content of malic acid remained stable or dropped, resulting in sweeter fruit. Levels of phenolics were more constant in the pulp of both cultivars analyzed, while in the peel, the changes were more pronounced. In the pulp, a peak in the content of hydroxycinnamic acids and flavanols was noticed on the 2nd or 3rd sampling and afterwards, the amounts remained constant. In the peel an initial decrease of all analyzed phenolic groups was observed in both cultivars, however it was more pronounced in "Jonagold." It can be concluded that changes in primary and secondary metabolites are not the main reason for the lower quality of fruit exposed to ambient temperatures. On the other hand, fruit firmness might be the limiting factor for shelf life duration.