辛明 李昌宝 孙宇 盛金凤 唐雅园 孙健 李杰民 李丽 何雪梅 零东宁

摘  要：為阐明采后百香果香气品质的变化特征，本研究采用顶空-固相微萃取（HS-SPME）结合气相色谱-质谱联用技术（GC-MS），研究了常温（25 ℃）、低温（6 ℃）贮藏期间百香果香气物质主要成分及其含量，酯类化合物代谢关键酶脂氧合酶（LOX）、醇酰基转移酶（AAT）、乙醇脱氢酶（ADH）和氢过氧化物裂解酶（HPL）活性的变化规律。结果表明：百香果在常温和低温贮藏期间，果汁中的香气物质均以酯类为主，相对含量分别占总香气物质的40.00%～60.32%和54.95%～69.27%，其次是醇类和酮类;进一步通过结构鉴定，在酯类物质中相对含量较高的化合物为丁酸乙酯、正己酸乙酯、丁酸己酯、乙酸乙酯、己酸己酯;常温下，百香果酯类物质相对含量在贮藏4 d时出现峰值（60.32%）、贮藏12 d时下降为40.00%，而低温下，其相对含量延至贮藏20 d时出现峰值（69.27%），整个贮藏期内保持在54.62%～69.27%，表明低温贮藏可以维持酯类物质较高的相对含量。对百香果酯类代谢途径关键酶活性分析发现，果汁中LOX、AAT和HPL在低温贮藏前期（0～10 d）活性变化不大，贮藏后期表现活跃，最高值出现时间迟于常温贮藏，表明低温可以有效抑制酯类代谢关键酶活性;另外，酯类香气化合物相对含量与LOX、AAT、ADH、HPL活性具有较强相关性。本研究为百香果采后品质保持和保鲜技术提供了参考依据。

关键词：百香果;香气成分;酯类;酶活性;相关性分析

中图分类号：TS255.3      文献标识码：A

Abstract： To clarify the variation characteristics of aroma quality in postharvest passion fruit， headspace-solid phase microextraction （HS-SPME） combined with gas chromatography-mass spectrometry （GC-MS） was used to determinethe main components and the contents in the fruit volatiles during storage at ambient temperature （25 ℃） and low tem-perature （6 ℃）. The present study further analyzed the activity variation rule of key enzymes in ester metabolism pathway， such as lipoxygenase （LOX）， alcohol acyltransferase （AAT）， alcohol dehydrogenase （ADH） and hydroperoxide lyase （HPL）. The results showed that the main aroma components in passion fruit juice were esters during storage at ambient and low temperatures， and their relative contents accounted for 40.00%-60.32% and 54.95%-69.27%， followed by alcohols and ketones. Furthermore， the main ester components with high relative contents were identified as ethyl butanoate， ethyl n-hexanoate， hexyl butyrate， ethyl acetate and hexyl hexanoate. During storage at ambient temperature， the relative content of esters in passion fruit peaked on 4th day （60.32%） and decreased to 40.00% on 12th day. However， this relative content peak appeared on 20th day （69.27%） and remained 54.62%-69.27% within the whole storage period at low temperature. Above results indicated that high relative content of esters could be maintained by low temperature storage. The analyses on key enzymatic activities in ester metabolism pathway showed that little variation of LOX， AAT and HPL activities appeared in passion fruit juice during early storage period （0-10 d） at low temperature. The enzymes were active during late storage period. The activity peaks appeared later than those at ambient temperature storage， indicating that low temperature could effectively inhibit the activities of key enzymes in ester metabolism pathway. In addition， the relative contents of ester components were strongly correlated with the activities of LOX， AAT， ADH and HPL. This study would provide reference for quality maintenance and postharvest preservation of passion fruit.

Keywords： passion fruit （Passiflora caerulea L.）; aroma components; esters; enzyme activity; correlation analysis

DOI： 10.3969/j.issn.1000-2561.2021.05.037

百香果為西番莲科（Passiflora caerulea L.）西番莲属（Passiflora）多年生常绿藤本植物，是热带亚热带地区特有水果[1-2]。我国主要分布在广西、福建、海南、广东、云南、台湾等地[3]，其中，广西、福建百香果产业发展较快，2017年两省栽培面积分别达14 000、6 700 hm2[4-5]。……