8个杂交柑橘品种的糖酸组分含量及特征研究

A study on the components and characteristics of sugars and acids in 8 hybrid citrus cultivars

【目的】明确8个新兴杂柑品种的糖酸组分及甜酸风味特征,为柑橘的品质评价及品种选育提供理论依据。【方法】分别采用离子色谱法和高效液相色谱法测定果实的糖、酸组成及含量,并以甜度值、甜酸比、糖酸比指标进行评价。【结果】可溶性总糖质量分数83.78~127.66 mg·g^-1,蔗糖占总糖的41.54%~64.60%,葡萄糖与果糖含量接近。总酸质量分数6.28~10.70 mg·g^-1,其中柠檬酸、苹果酸、莽草酸含量分别占总酸含量的45.58%~88.06%、7.84%~53.22%和1.14%~9.59%';春香''091沃柑'的苹果酸含量较高',黄美人'的莽草酸含量最高',红美人'的总甜度、甜酸比和糖酸比均为最高。以甜酸比、糖酸比对各品种品质评价排序较一致,固酸比偏差较大。【结论】'黄美人''明日见''甘平'的糖以己糖与蔗糖的形式共同积累,其余以蔗糖为主';春香'和'091沃柑'的苹果酸和柠檬酸比例相近,其余以柠檬酸为主。建议以甜酸比或糖酸比为杂柑类品质评价指标。

【Objective】Fruit quality is an important basis for evaluating fruit varieties and determines their competitiveness in the market.Sugar and acid components are important indicators of fruit flavor and quality.Hybrid citrus from natural or artificial hybridization between citrus species have the characteristics of nutrition,flavor and peeling easiness of citrus,tangerine,orange,or pomelo.Therefore,hybrid citrus play an important role in the adjustment of the citrus variety structure.At present,research on hybrid citrus mainly focuses on the aspects of botanical characters,biological characteristics and cultivation techniques,and very few studies have made on fruit quality,especially sugar and acid composition.This paper comprehensively evaluated the sugar and acid components and sweet-sour flavor characteristics of 8 introduced hybrid citrus cultivars in Zhejiang.【Methods】Ion chromatography and highperformance liquid chromatography were used to determine the compositions and contents of sugars and acids in the fruits,and the sweetness value,sweet-sour ratio,and sugar-acid ratio were used as the indexes for evaluation.An ion chromatography electrochemical detector and a standard four-potentia acquisition method with a PA10 anion exchange column(4 mm×250 mm)and the same type of guard column were used to determine sugar components.Mobile phase A was water while B was 200 mmoL·L-1NaOH with gradient elution and equilibration for 5 min.High-performance liquid chromatography with a C18 column(4.6 mm×300 mm,5μm)and the same type of guard column was used to determine acid components.The column temperature was 40℃,the flow rate was 0.5 mL·min^-1,the detection wavelength was 210 nm,and the mobile phase was KH2PO4buffer with a pH value of 2.65(containing 0.5%methanol).The collection time was 35 min and quantification was made using the external standard method.The soluble solids(TSS)were measured by a Brix meter(PAL-1),and the titratable acid(TA)was measured with titration.Data processing and statistical analysis were performed using Microsof Excel 2007 and SPSS 19.0 software,respectively.【Results】The total sugar content in fruits of the 8 citrus cultivars was in the range of 83.78-127.66 mg·g-1,in an order of’Hongmeiren’>’Huangmeiren’>’Kanpei’>’Asumi’>’Orah 091’>’Haruka’>’Himekoharu’>’Harumi’,and the main sugar components were glucose,fructose and sucrose.Sucrose accounted for 41.54%-64.60%of the total soluble sugars,and the contents of glucose and fructose were similar.The total acid content ranged between 6.28 and 10.70 mg·g-1,and the content of citric acid,malic acid and shikimic acid accounted for 45.58%-88.06%,7.84%-53.22%and 1.14%-9.59%of the total acid content,respectively.The tota acid content in the eight hybrid citrus cultivars was in the order of’Kanpei’>’Asumi’>’Huangmeiren’>’Hongmeiren’>’Himekoharu’>’Harumi’>’Orah 091’>’Haruka’.The content of malic acid in’Haruka’and’Orah 091’was higher than in the other cultivars,and the contents of fructose glucose and shikimic acid in’Huangmeiren’were the highest.’Hongmeiren’had the highest tota sweetness,sweet-sour ratio and sugar-acid ratio.The taste of the 8 hybrid citrus cultivars fell in 5grades including sour,sweet,sweet-sour,palatable sour-sweet and sour-sweet,and the rate of sweetsour was in the order of’Hongmeiren’>’Huangmeiren’>’Orah 091’>’Haruka’>’Asumi’>’Himekoharu’>’Harumi’>’Kanpei’.The total sweetness of’Kanpei’was not low,because of the influence of organic acids,its sweet-sour ratio and sugar-acid ratio were the smallest among the 8 hybrid citrus.【Conclusion】The sugars of’Huangmeiren’,’Asumi’and’Kanpei’among the 8 hybrid citrus accumulated both hexose and sucrose,while the other 5 varieties accumulated mainly sucrose.The sum of citric acid and malic acid in the 8 hybrid citrus cultivrs accounted for>90%of the total acids The ratio of malic acid to citric acid in’Haruka’and’091 Wokan’was similar,and the others were dominated by citric acid.Due to the differences in the contribution of sugar and acid components to taste,the sweet-sour ratio,sugar-acid ratio and solid-acid ratio were used in this study to rank the varieties.The results of sugar-acid ratio and sweet-sour ratio were generally consistent,but the evaluation results based on solid-acid ratio,sweet-sour ratio and sugar-acid ratio had greater deviations.Finally,i was suggested that the sweet-sour ratio or sugar-acid ratio can be used as the quality evaluation index This study provides data for selection and promotion of citrus varieties as well as reference of citrus flavors for consumers.