采前喷施胺鲜酯对采后龙眼果实贮藏期间果皮能量代谢的影响

本实验研究采前喷施含量为10 mg/kg的胺鲜酯(diethyl aminoethyl hexanoate,DA-6)对采后'福眼'龙眼果实(Dimocarpus longan Lour.cv.Fuyan)贮藏期间果皮能量代谢的影响.贮藏期间取样测定龙眼果实的果皮腺苷三磷酸(adenosine triphosphate...     

Effect of pure oxygen atmosphere on antioxidant enzyme and antioxidant activity of harvested litchi fruit during storage

The effects of pure oxygen on pericarp browning, reactive oxygen species (ROS) metabolism, antioxidant enzyme and antioxidant activity of harvested litchi fruit were investigated. Application of pure oxygen significantly prevented pericarp browning and delayed the increase in membrane permeability of litchi fruit during storage. Litchi fruit exposed to pure oxygen showed a lower level of lipid peroxides, compared to control fruit, with the delay in the increases of both H₂O₂ content and superoxide production rate. Furthermore, it was found that the treatment with pure oxygen induced the activities of superoxide dismutase (SOD), ascorbated peroxidase (APX) and catalase (CAT), which could be beneficial in scavenging of H₂O₂ and superoxide and alleviating lipid peroxidation. In addition, antioxidant ability (reducing power and free-radical scavenging activity against DPPH radical, superoxide anions and hydroxyl radical) of methanol extracts from litchi fruit pericarp declined gradually, with decreasing contents of anthocyanins and phenolic compounds, as storage time of the fruit progressed. There was a linear relationship between the contents of either anthocyanins or phenolic compounds and antioxidant ability or free radical scavenging activity. Treatment with pure oxygen markedly increased antioxidant ability, which was related to higher levels of anthocyanins and phenolic compounds, compared with those of control fruit. It is suggested that enhanced antioxidant activity and antioxidant enzyme induced by pure oxygen may contribute to alleviating lipid peroxidation and maintenance of membrane integrity, which reduced decompartmentation of enzymes and substrates, resulting in enzymatic browning.     

壳聚糖对荔枝果皮渗漏性及贮藏时间的影响

通过分析经壳聚糖涂膜处理的荔枝果实在贮藏期间果皮细胞的渗漏率的变化,研究果皮细胞电解质渗漏性与果实贮藏性能之间的关系。在研究的29、22、15和8℃4个温度范围内,随贮藏温度下降,果皮渗漏率降低,果实贮藏时间延长。在贮藏时间范围内,渗漏率表现为先是升高至峰值,然后下降。渗漏率开始发生下降后,果实失去商品价值。并且渗漏率峰值出现得越晚,果实贮藏时间越长。渗漏率(X)与褐变指数(Y)呈显著的正相关(R=0.9506),其回归方程为Y=0.0683X-1.0039。壳聚糖涂膜处理明显抑制荔枝果皮细胞的渗漏率,果实贮藏时间较长。     

ATP-regulation of antioxidant properties and phenolics in litchi fruit during browning and pathogen infection process

The impact of energy level on antioxidant properties in relation to pericarp browning and loss of disease resistance of litchi fruit was investigated. Litchi fruits were vacuum-infiltrated with distiled water (control), 1 mM adenosine triphosphate (ATP) and 0.5 mM 2,4-dinitrophenol (DNP) under 75 kPa for 3 min before being inoculated with Peronophythora litchi or not. ATP-treated fruits presented higher activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX). Higher activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power and contents of phenolic compounds were also observed in ATP-treated fruit during storage. In contrast, DNP treatment lowered the enzymes activities, scavenging ability and the contents of phenolic compounds. Higher levels of antioxidant enzymatic system and non-enzymatic system were observed in P. litchii-inoculated fruits than those in non-inoculated fruits. Application of ATP and DNP exhibited a similar change patterns and effects in inoculated fruits. When related to previously reported ATP levels, the results suggested that ATP levels could regulate the antioxidant system. Sufficient available energy is crucial for inhibiting browning and preventing the loss of disease resistance in harvested litchi fruit.     

Antioxidant properties of anthocyanins extracted from litchi (Litchi chinenesis Sonn.) fruit pericarp tissues in relation to their role in the pericarp browning

Anthocyanins were extracted and purified from litchi fruit pericarp and their antioxidant properties were investigated. Effects of exogenous anthocyanin treatments on pericarp browning and membrane permeability of harvested litchi fruit were also evaluated. Anthocyanins from litchi fruit pericarp strongly inhibited linoleic acid oxidation and exhibited a dose-dependent free-radical-scavenging activity against DPPH radical, superoxide anions and hydroxyl radical. The degradation of deoxyribose by hydroxyl radicals was shown to be inhibited by anthocyanins acting mainly as chelators of iron ions rather than directly scavenging hydroxyl radicals. Anthocyanins were also found to have excellent reducing power. The reducing power of anthocyanins, ascorbic acid and butylated hydroxytoluene all at 100 μg/ml were 3.70, 0.427 and 0.148, respectively, indicating that anthocyanins from litchi pericarp had a strong electron-donating capacity. Furthermore, application of anthocyanins to harvested litchi fruit significantly prevented pericarp browning and delayed the increase in membrane permeability. It was therefore suggested that anthocyanins could be beneficial in scavenging free radicals and reducing lipid peroxidation of litchi fruit pericarp.     

IDENTIFICATION OF PROCYANIDIN A2 AS POLYPHENOL OXIDASE SUBSTRATE IN PERICARP TISSUES OF LITCHI FRUIT

Postharvest browning of litchi fruit results in short shelf life and reduced commercial value. Experiments were conducted to separate, purify and identify polyphenol oxidase (PPO ) substrates that cause litchi fruit to brown. PPO and its substrate were extracted from the pericarp tissues of litchi fruit. The litchi PPO substrate was purified using polyamide column, silica gel column and Sephadex LH‐20 column chromatography. The browning substrate was selected by a 0.5% FeCl₃ solution and then identified using a partially purified litchi PPO. Analyses of ultraviolet spectrometry, nuclear magnetic resonance and electrospray ionization mass spectrometry indicated that the PPO substrate was procyanidin A2. The substrate can be oxidized to ο‐quinones by litchi PPO and then form brown‐colored by‐products, resulting in pericarp browning of harvested litchi fruit.     

Effect of oxalic acid on control of postharvest browning of litchi fruit

Litchi (Litchi chinensis Sonn.) fruit, cv. Huaizhi, was treated with 2 and 4 mM oxalic acid and stored at room temperature to investigate the effect of oxalic acid on pericarp browning. The results showed that the pericarp browning indices of the fruit, treated with both oxalic acid concentrations, were significantly lower than that of the control, due to increase of membrane integrity, inhibition of anthocyanin degradation, decline of oxidation, and maintanance of relatively low peroxidase activity in the fruit during storage. It appears that application of oxalic acid can effectively control the pericarp browning of litchi fruit during postharvest storage.     

低温预贮对冷藏桃果实冷害及能量水平的影响

研究了低温预贮对桃果冷害和能量水平的影响。桃果实先在12℃预贮6d,随后于0℃贮藏30d, 每隔5d测定果实褐变指数、硬度和出汁率等冷害指标、H+-ATPase、Ca2+-ATPase、琥珀酸脱氢酶、细胞色素氧化酶等线粒体呼吸代谢相关酶活性及能量相关物质ATP、ADP、AMP含量和能荷变化。结果表明：低温预贮处理可有效抑制果实H+-ATPase、和Ca2+-ATPase活性的下降,保持较高的琥珀酸脱氢酶和细胞色素氧化酶活性,使得ATP、ADP的含量及能荷保持较高水平,减少膜脂过氧化产物丙二醛(MDA)的积累和细胞膜透性增加,延缓果实出汁率下降,抑制果实褐变指数的升高。结果表明：低温预贮处理通过调节线粒体呼吸代谢酶活性,维持果实较高的能量水平,从而延缓膜脂过氧化进程,减轻果实冷害的发生。     

不同厚度PE袋对冷链物流过程中荔枝褐变的影响

本研究采用厚度为10、20、30 μm的聚乙烯袋包装‘鸡嘴荔’荔枝,结合冰袋模拟物流包装,研究在当前冷链物流体系不完善情况下对荔枝果皮褐变、细胞膜透性、花青素代谢的影响。结果表明:在贮藏过程中通过对果皮褐变、适销果比率及果实色差分量变化分析发现20 μm聚乙烯袋包装效果较好,其次是10 μm厚度,最差是30 μm。并且20 μm厚度聚乙烯袋显著抑制细胞膜透性上升,这体现为贮藏期间果实组织更低的相对电导率（P<0.05）。进一步研究结果表明:聚乙烯袋（20 μm）能通过抑制花青素生物合成中的关键酶苯丙氨酸解氨酶活性延缓花青素分解,并结合抑制多酚氧化酶和过氧化物酶活性延缓荔枝果皮褐变。综上,20 μm聚乙烯袋相对于其它厚度可明显抑制荔枝褐变,有效保持果实品质,延长货架期。     

INHIBITORY EFFECT OF ANTHOCYANIN EXTRACT FROM SEED COAT OF BLACK BEAN ON PERICARP BROWNING AND LIPID PEROXIDATION OF LITCHI FRUIT DURING STORAGE

ABSTRACT

Anthocyanins were extracted from seed coats of black beans (Glycine max[L.]) and the inhibitory effects of anthocyanin extract on pericarp browning and lipid peroxidation of litchi fruit were investigated. Litchi fruit were infiltrated for 3 min with 0 (control) or 50 mg/L of anthocyanin extract at a reduced pressure of 53 kPa, then packed in 0.03 mm thick polyethylene bags, and finally stored at 28C for 6 days. Changes in browning index, contents of anthocyanins and total phenol, peroxidase (POD) activity, levels of relative leakage rate and lipid peroxidation, α,α‐diphenyl‐β‐picrylhydrazy (DPPH) radical scavenging activity and reducing power were evaluated. Application of anthocyanin extract from black bean delayed pericarp browning of litchi fruit during storage, which was associated with reduced POD activity and higher contents of anthocyanins and total phenol. Moreover, the anthocyanin extract was found to have a direct inhibition on the POD activity in vitro. Furthermore, application of the anthocyanin extract apparently reduced lipid peroxidation and relatively maintained membrane integrity, which may account for browning inhibition to an extent. Finally, higher DPPH radical scavenging activity and reducing power of the fruits treated with the anthocyanin extract than control fruits possibly benefited in scavenging free radicals and reducing lipid peroxidation. It is, therefore, suggested that inhibited POD activity and reduced lipid peroxidation by the anthocyanin extract from seed coats of black beans were responsible for the inhibition of pericarp browning of litchi fruits.

PRACTICAL APPLICATIONS

Lipid peroxidation is a major cause of quality deterioration of postharvest fruits and vegetables. Some synthetic antioxidants are beneficial in inhibiting lipid peroxidation. However, considering that synthetic antioxidants, such as butylhydroxyanisole and butylated hydroxytoluene (BHT), have potential toxicity, the use of natural extracts to extend the shelf life of postharvest fruits and vegetables is a tendency. In our previous study, it has been found that anthocyanin extract from litchi pericarp has stronger antioxidant activities or free radical scavenging activities than BHT and ascorbic acid ( Duan et al. 2007 ). In this study, the application of anthocyanin extract from seed coat of black soybean showed reduced lipid peroxidation and pericarp browning. It could be used potentially as a postharvest technology for reducing or replacing the use of other chemicals, but it requires further investigation.     

Fruit quality and physiological responses of litchi cultivar McLean's Red to 1-methylcyclopropene pre-treatment and controlled atmosphere storage conditions

The effect of 1-MCP pre-treatment and two different controlled atmosphere storage conditions (CA-1, 17% O₂ + 6% CO₂; CA-2, 7% O₂ + 3% CO₂) on fruit quality parameters and physiological changes with respect to pericarp browning in ‘McLean's Red’ litchi were investigated. Fruits were pre-treated with 1-MCP (500 nl/l) and held at CA-1 or CA-2 for 21 d at 2 °C and at 90% RH. Stand-alone CA-1 or stand-alone CA-2 and the commercially adopted sulphur dioxide (SO₂) treatment were included in this study for comparison. Of the five treatments 1-MCP + CA-1 was most effective in preventing browning, loss of red colour (colour value a*) of the pericarp, ascorbic acid content; and retaining acceptable SSC/TA and taste. Fruit from 1-MCP + CA-1 showed higher overall acceptance after 21 d storage without any off-flavour according to the sensory panel data.1-MCP + CA-1 reduced the polyphenol oxidase (PPO) and peroxidase (POD) activity, retained membrane integrity and anthocyanin content during storage. Although SO₂ treatment prevents browning it showed negative effects on SSC/TA, taste and membrane integrity. Stand-alone CA-2 condition indicated higher pericarp browning, PPO, POD activity and loss of membrane integrity. Therefore, 1-MCP pre-treatment and CA-1 retains overall fruit quality for up to 21 d.     

葡萄果肉组织的能量水平和细胞壁代谢对其自溶软化的影响

为研究葡萄采后贮藏过程中自溶软化与能量水平及细胞壁代谢的关系,比较贮藏初期和末期果皮超微结 构的变化。采后葡萄经钙联合涂膜和热处理后,低温（（4.0±0.5） ℃）贮藏,定期测定果肉自溶指数、硬度、 腐烂率、膜透性、能量物质（三磷酸腺苷（adenosine triphosphate,ATP）、二磷酸腺苷（adenosine diphosphate, ADP）、单磷酸腺苷（adenosine monophosphate,AMP））含量及能荷（energy charge,EC）、细胞壁降解酶活 力和细胞壁成分的变化,扫描电子显微镜观察贮藏初期和末期不同处理果实内果皮的超微结构,以未处理组为对 照。结果显示：随贮藏时间的延长,果实自溶指数、腐烂率和膜透性升高,硬度和能量物质下降,多聚半乳糖醛 酸酶（polygalacturonase,PG）、果胶甲酯酶（pectinesterase,PE）和纤维素酶（cellulase,Cx）活力上升,β-半 乳糖苷酶（β-galactosidase,β-Gal）活力在贮藏30 d内下降,之后急剧升高。细胞壁组分原果胶、纤维素和半纤 维素含量下降,水溶性果胶含量前期上升,后期下降;葡萄内果皮的超微结构破坏,出现了大的孔洞。葡萄果实 自溶指数与能量水平、细胞壁降解酶活力和细胞壁组分紧密相关,果实自溶指数与ATP、ADP含量极显著负相关 （P＜0.01）,和AMP显著负相关（P＜0.05）,与EC无明显相关性（P＞0.05）;与PG、PE、Cx活力极显著正相 关（P＜0.01）,与β-Gal活力无明显相关性（P＞0.05）;与原果胶、水溶性果胶、纤维素和半纤维素含量极显著负 相关（P＜0.01）。钙联合涂膜和热处理能够维持组织的高能量状态和致密的超微结构,抑制PG、PE和Cx活力的升 高,延缓细胞壁降解,延缓自溶软化,其中涂膜显著优于热处理（P＜0.05）。     

基于主成分分析的硝普钠处理对采后荔枝活性氧代谢的影响

为探究外源NO处理对荔枝采后活性氧代谢及生理品质的影响,本实验以不同浓度(10、50、100 μmol/L)硝普钠对采后荔枝进行浸泡处理,以清水处理为对照组,在4 ℃下定期测定荔枝的生理指标的变化,并进行相关性分析与主成分分析。结果表明：硝普钠处理能明显降低荔枝果实的质量损失率,抑制过氧化氢和超氧阴离子自由基等活性氧的产生和积累,减少膜脂过氧化产物丙二醛的产生和降低细胞膜透性,提高抗氧化酶如超氧化物歧化酶（superoxide dismutase,SOD）活力,延缓荔枝的衰老和褐变;10 μmol/L硝普钠处理能明显延缓荔枝褐变指数上升和降低果实细胞膜透性,而100 μmol/L处理组在贮藏中后期能更有效地降低果实质量损失率和提高SOD活力;主成分分析和品质综合评价结果表明,影响荔枝采后品质的关键指标为褐变指数、细胞膜透性、质量损失率和SOD活力,且100 μmol/L硝普钠处理的果实在贮藏后期（6 d后）的综合得分更高,贮藏品质最佳,表明硝普钠处理可以有效通过调节活性氧代谢延缓荔枝衰老褐变,延长其保质期。     

BROWNING INHIBITION AND QUALITY MAINTENANCE OF FRESH-CUT CHINESE WATER CHESTNUT BY ANOXIA TREATMENT

Experiments were conducted to test the effects of anoxia treatments on the quality of fresh‐cut Chinese water chestnut (CWC). Fresh‐cut CWC was exposed to pure N₂ for 0 (control) or 4 h, then placed in trays overwrapped with plastic film and finally stored at 4C. Changes in surface discoloration, eating quality, disease incidence, concentrations of total soluble solids and titratable acidity, activities of phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), and membrane permeability were analyzed. The short‐term anoxia treatment significantly inhibited surface discoloration and disease development, and markedly reduced the loss of eating quality in association with a higher concentration of total soluble solids. Exposure of fresh‐cut CWC to pure N₂ gas for 4 h significantly reduced membrane permeability, but it increased PAL and PPO activities. Thus, the browning inhibition of the fresh‐cut CWC by the short‐term anoxia treatment may be because of the maintenance of compartmentation between enzymes and their substrates, preventing enzymatic reaction. The result suggests that short‐term anoxia treatment exhibits potential for extending the shelf life of fresh‐cut CWC.     

低温贮藏对晚熟龙眼“立冬本”果实采后生理和品质的影响

研究了龙眼"立冬本"果实在采后(25±0.5)℃和(3±0.5)℃温度下的呼吸强度、细胞膜透性和品质的变化。结果表明:龙眼果实属于非呼吸跃变型果实;在(25±0.5)℃下贮藏4天,果实呼吸强度下降,之后明显上升;果实采后果皮细胞膜透性快速增加,果实易失重、衰老、腐烂和果皮褐变,贮藏后期果肉自溶;果肉可滴定酸和维生素C含量快速下降,总糖和蔗糖含量下降,还原糖含量先升后降,可溶性固形物含量在贮藏前期下降而后期上升,可溶性固形物和可滴定酸比值先升后降;贮藏后期果肉可滴定酸含量增加。而(3±0.5)℃低温贮藏可显著降低果实呼吸强度,抑制病原菌生长,延缓果实衰老和果皮细胞膜透性增加,延迟果皮褐变,减少果实失重和果肉营养成分变化,抑制果肉自溶,保持果实较高的品质,延长果实贮藏期。     

EFFECT OF OXYGEN CONCENTRATION ON THE BIOCHEMICAL AND CHEMICAL CHANGES OF STORED LONGAN FRUIT

ABSTRACT

Longan fruits were stored for 6 days in atmosphere of 5, 21 (air) or 60% O₂ (balance N₂) at 28C and 90–95% relative humidity to examine effects of low and high O₂ concentration on enzymatic browning and quality attributes of the fruit. Changes in pericarp browning, pulp breakdown, disease development, total phenol content, activities of phenol metabolism‐associated enzymes, relative leakage rate, α,α‐diphenyl‐β‐picrylhydrazy (DPPH) radical scavenging activity, and contents of total soluble solids, titratable acidity and ascorbic acid were evaluated. Storage of fruit in a 5% O₂ atmosphere markedly delayed pericarp browning in association with maintenance of high total phenolic content and reduced activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase. Moreover, the fruit stored in a 5% O₂ atmosphere exhibited a lower relative leakage rate and higher DPPH radical scavenging activity than fruit stored in air. This presumably was beneficial in maintaining compartmentation of enzymes and substrates, and thus, reducing pericarp browning. Pulp breakdown and disease development were also reduced by exposure to a 5% oxygenatmosphere. On the contrary, exposure of longan fruit to a 60% O₂ atmosphere accelerated pericarp browning, pulp breakdown and decay development. PPO and POD activities and relative leakage rate were similar for control and 60% O₂‐treated fruit after 4 and 6 days of storage. Furthermore, treatment with 60% O₂ significantly decreased the phenolic content and DPPH scavenging activity of fruit. In addition, exposure to 5 or 60% O₂ resulted in a higher level of total soluble solids, but a lower level of ascorbic acid of longan fruit flesh. In conclusion, exposure to a 5% O₂ atmosphere showed great potential to reduce pericarp browning and extend shelf life of longan fruit.

PRACTICAL APPLICATIONS

Pericarp browning and pulp breakdown are the major causes of deterioration in postharvest longan. Conventional controlled atmosphere with low O₂ and high CO₂ is effective in maintaining quality and extending shelf life of fruits and vegetables, including inhibition of tissue browning. In this study, 5%‐controlled atmosphere reduced significantly pericarp browning, pulp breakdown and rot development. It could potentially be useful as a postharvest technology of longan fruit for reducing or replacing the use of chemicals such as SO₂ and fungicides, but it requires further investigation.     

脱硫对熏硫‘黑叶’荔枝采后品质及果肉亚硫酸盐代谢的影响

本实验研究了脱硫对熏硫‘黑叶’荔枝果实采后品质、亚硫酸盐残留量和果肉中亚硫酸盐代谢的影响。测定对照（施保克）、熏硫和脱硫处理的果实4 ℃贮藏期间的色度值、褐变指数、腐烂率、亚硫酸盐残留量及果肉中亚硫酸盐氧化酶（sulfite oxidase,SO）、腺苷-5’-磷酰硫酸还原酶（adenosine 5’-phosphosulfatezoline reductase,APR）、亚硫酸盐还原酶（sulfite reductase,SiR）、丝氨酸酰基转移酶（serine acetyltransferase,SAT）和乙酰丝氨酸裂解酶（O-acetylserine (thiol) lyase,OAS-TL）活力和基因表达。结果表明：贮藏期间脱硫果实较熏硫果实提前转红;脱硫和熏硫荔枝的果皮褐变指数和腐烂率均较对照组显著降低;相比熏硫,脱硫使果皮水分质量分数降低和相对电导率升高的幅度更大,抑制呼吸的效果则相近;脱硫使果皮亚硫酸盐含量大幅降低,并使得果肉亚硫酸盐含量在贮藏16 d后降至接近对照组的水平;贮藏期间除APR外,熏硫和脱硫后果肉中其他4 种酶的活力均呈现上调,即贮藏过程中处理组SO、SAT活力分别较同时期对照组上调2.0、8.6～26.7 倍,而脱硫果肉SAT活力仅在贮藏0 d较对照组上调11.1 倍,之后迅速下降,贮藏32 d后与对照组无显著差异;熏硫和脱硫果肉中5 个基因的表达则均在贮藏中后期总体高于对照。上述结果表明,脱硫可加快熏硫荔枝果皮恢复红色,获得与熏硫相当的保鲜效果,大幅降低了熏硫荔枝的硫残留,保障其食用安全。脱硫和熏硫荔枝果肉中SO和SAT活力的上调表明,SO酶促氧化反应是荔枝果肉亚硫酸盐降解中占主导和最稳定的方式,SAT和SiR主导的还原途径则可能作为氧化途径的补充。     

Effects of O2 and CO2 concentrations on physiology and quality of litchi fruit in storage

Litchi (Litchi chinensis Sonn. cv Heiye) fruit were stored in air, modified atmosphere packaging (MAP) and controlled atmospheres (CA) at 3 °C to determine the effects of different O₂ and CO₂ atmospheres on physiology, quality and decay during the storage periods. The results indicated that CA conditions were more effective in reducing total phenol content, delaying anthocyanidin decomposition, preventing pericarp browning, and decreasing fruit decay in comparison with MAP treatment. Polyphenol oxidase (PPO), peroxidase (POD), anthocyanin and total phenols were involved in cellular browning. High O₂ treatment significantly limited ethanol production of litchi flesh in the early period of storage. The fruit stored in CA conditions for 42 days maintained good quality without any off-flavour.     

Antioxidant activities and contents of polyphenol oxidase substrates from pericarp tissues of litchi fruit

The experiments were performed to extract and purify substrates for polyphenol oxidase (PPO) from pericarp tissue of postharvest litchi fruit. Two purified PPO substrates were identified as (−)-epicatechin and procyanidin A2. The antioxidant properties of two PPO substrates were further evaluated in the present study. Variation in the content of the major substrate (−)-epicatechin of litchi fruit during storage at 25 °C was analysed using the HPLC-UV method. The results showed that (−)-epicatechin exhibited stronger antioxidant capability than procyanidin A2, in terms of reducing power and scavenging activities of DPPH radical, hydroxyl radical and superoxide radical. Furthermore, (−)-epicatechin content in pericarp tissue tended to decrease with increasing skin browning index of litchi fruit during storage at 25 °C. Thus, these two compounds can be used as potential antioxidants in litchi waste and the fresh pericarp tissue of litchi fruit exhibited a better utilisation value.