不同成熟阶段五种柚果实的主要理化品质和挥发性成分变化规律

Changes in main physical and chemical quality and volatile components of five pomelo fruits at different maturation stages

为了探究柚果实生长过程中理化品质和挥发性成分的动态变化规律,选取了西南地区5种特色柚果(东风早柚、长寿沙田柚、梁平柚、龙安柚和丰都红心柚),分析了5个成熟阶段主要理化品质和挥发性成分。外在品质中,柚果实的质量、横纵径与成熟期呈正比,果皮厚度与成熟期呈反比;内在品质中,随着成熟期的延长,柚果实的出汁率、可食率和可溶性固形物含量均有上升趋势,可滴定酸含量显著下降,维生素C含量则呈现先升高后降低的趋势。5个成熟阶段期间,在5个品种柚果实中共检出52种挥发性成分,其中萜类20种(包括单萜10种、倍半萜10种)、醇类9种、醛类10种、酯类8种、酮类2种、其他3种。在整个成熟阶段,挥发性物质总量呈以下规律:商业成熟期>成熟转色期>生长膨大期>幼果期>膨大期。随着成熟期的延长,萜类物质占比始终是最高的,为82.8%~96.4%。柠檬烯是最丰富的萜类物质,其占比萜类为67.7%~90.1%,其变化规律与萜类物质和总挥发性物质是一致的;月桂烯、β-蒎烯和α-蒎烯是较丰富的单萜物质;α-石竹烯、大牛儿烯D和β-石竹烯也是较丰富的倍半萜物质。醇类、醛类物质是仅次于萜类的挥发性物质,占比分别为1.6%~13.4%和0.3%~6.8%。此外,少量的酯类、酮类、其他物质也存在于柚果实中。该研究为我国柚果营养品质特性的探究提供参考,同时也为柚果资源的加工利用提供数据支持。

To investigate the dynamic changes of physical and chemical quality and volatile components during the growth process of pomelo fruits,five characteristic pomelo fruits(Dongfengzao pomelo,Changshou Shatian pomelo,Liangping pomelo,Long′an pomelo,and Fengdu Hongxin pomelo)from southwest China were selected.The main physical and chemical quality and volatile components in the five mature stages were analyzed.For the external quality,the weight and horizontal and vertical diameter of pomelo fruit were in direct proportion to maturity,while the peel thickness was in inverse proportion.For the internal quality,the juice yield,edible rate,and soluble solid contents of pomelo fruit all increased,and the titratable acid content decreased significantly.With the extension of maturity,vitamin C content increased first and then decreased.A total of 52 volatile components were detected in the fruits of 5 varieties of pomelo,including 20 terpenes(10 monoterpenes and 10 sesquiterpenes),9 alcohols,10 aldehydes,8 esters,2 ketones,and 3 others.As the maturity period prolonged,the total amount of volatile substances followed the pattern:commercial maturity period>mature color transition period>growth and expansion period>young fruit period>expansion period.As the maturity period extended,the proportion of terpenes remained the highest,ranging from 82.8%to 96.4%.Limonene was the most abundant terpene substance,accounting for 67.7%-90.1%of terpenes.Its variation pattern was consistent with that of terpenes and total volatile compounds.Myrcene,β-pinene andα-pinene were relatively abundant monoterpene substances.α-Caryophyllene,germacrene D,and β-caryophyllene were also relatively abundant sesquiterpene substances.Alcohols and aldehydes were volatile substances second only to terpenes,accounting for 1.6%-13.4%and 0.3%-6.8%,respectively.In addition,a small amount of esters,ketones,and other substances were also present in pomelo fruits.This article provides a basis for exploring the nutritional quality characteristics of pomelo fruits in China and also provides data support for the processing and utilization of pomelo fruit resources.