【作者】 李丽；

【导师】 孟宪军；

【作者基本信息】 沈阳农业大学 ， 食品科学与工程， 2016， 博士

【摘要】 草莓不仅富含丰富的营养,而且草莓在多种疾病的预防上有积极的作用。我国草莓资源无论是产量还是种植规模在世界均名列前茅,但是草莓的综合利用率相对较低,主要是受评价体系及深加工技术的限制。本文主要针对草莓原料进行评价研究,为我国草莓在加工品种的资源利用及选育方面,提供全面、科学的加工品质特性方面的评价方法,同时以此筛选适合速冻加工的原料,为促进草莓速冻深加工提供理论依据,草莓综合品质评价体系的建立对草莓加工业的发展有着重要的指导意义。本研究以辽宁地区12个主栽品种草莓为原料,采用单体速冻工艺加工制成速冻草莓。测定并分析草莓原料的14项品质指标和速冻草莓的12项品质指标进行测定,应用统计分析学中的主成分分析及相关性分析,对影响草莓原料及速冻草莓品质的核心指标进行筛选确定。为消除不同指标间的纲量及数量级的影响,需要对核心评价指标数据进行数据的标准化处理,利用层次分析法对指标进行草莓原料及速冻草莓品质评价模型的构建。将标准化的草莓原料指标与速冻草莓综合值结合,应用统计分析中的逐步分析回归分析,建立速冻草莓与原料品质关联模型。旨在为草莓产业的发展和草莓品质评价提供科学依据和技术支撑。通过对草莓原料及速冻草莓的品质研究,得出如下结论：(1)草莓原料品质指标分析显示：14个品质指标在不同品种间存在不同程度的变异,其中,L值、粗蛋白、可溶性固形物和含水量的变异系数<10%,这4个指标的差异较小,品种间差异不显著。其余10项指标的变异系数较大(即>10%),各品质指标数据差异显著。对草莓原料14个指标进行相关性分析,指标间存在105个相关系数,其中在a=0.05水平上有7个显著相关性,在a=0.01水平上有4个相关性。指标中的绝大多数无显著相关性。(2)从14项草莓原料品质指标中筛选出6个核心品质的评价指标,分别为：颜色a值、糖酸比、硬度、花色苷、总酚和Vc。利用层次分析法对核心指标进行权重赋予,建立草莓原料综合评价模型：Y综合值=0.311358x颜色a值+0.311358x糖酸比+0.167618×硬度+0.06836x花色苷+0.057249×总酚+0.084058×维生素C,利用感官评分法对草莓原料进行评分,草莓原料感官评分结果与其对应的综合评价值进行线性回归分析,得到的相关系数为0.9248。(3)速冻草莓品质指标分析显示：总酚、可溶性固形物、可溶性糖以及汁液流失率,这4项品质指标具有较低的变异系数(<10%),离散程度较小,未体现明显品种间差异性；余下8个品质指标变异系数较大(>10%),均体现出了品种间的差异性。12项指标的相关性分析结果显示：相关系数在α=0.05水平上相关的有5个,在α=0.01水平上相关的有3个。(4)确定7个速冻草莓核心评价指标：a值、糖酸比、总酚、花色苷、Vc、硬度和汁液流失率。利用层次分析法对核心指标进行权重赋予,建立草莓原料综合评价模型：Y综合值=0.288285×糖酸比+0.288285×a值+0.092462×花色苷+0.150529×硬度+0.092083×总酚+0.056268×Vc+0.032088×汁液流失率。利用感官评分法对速冻草莓进行评分,速冻草莓感官评分结果与其对应的综合评价值进行线性回归分析,得到的相关系数为0.9106。(5)速冻草莓的7个核心指标与对应的原料品质多项指标显著相关,12个品种草莓建立速冻草莓品质与原料品质关联模型：Y综合值=0.851-0.664×总酚-0.497×糖酸比+0.295×含水量+0.160×硬度。(6)速冻对香气影响显著：99和章姬草莓醛类变化最为明显,其中99草莓速冻后醛类物质增加明显,章姬草莓醛类物质下降明显；速冻对R7草莓酯类物质影响明显,速冻后减少了42.35%；R7、99和章姬三种草莓速冻后醇类变化显著,R7和章姬草莓速冻后醇类物质升高明显,99草莓速冻后醇类物质明显减少；全明星、四季、R7和章姬四个品种草莓速冻后酮类物质均增长显著,其中R7草莓是酮类物质含量变化最为显著高于其他品种,速冻前后R7草莓甜香味儿较原料变化明显,速冻对99草莓酮类物质影响不显著。(7)草莓速冻处理的果实能较好的保留其酯类成分。速冻处理草莓冻藏5个月的酯类香气成分及含量显著高于同时期缓冻草莓。冻藏过程中,速冻草莓中的LOX活性失活程度比缓冻草莓要小,它们之间的差异不显著,速冻和缓冻冻藏过程中AAT和ADH活性及基因表达水平的降低,可能与草莓果实酯类香气变淡有关。更多还原

【Abstract】 Strawberry is rich in nutrient elements and high medicinal value. The strawberry resources and planting scale come up top in the world, but the comprehensive utilization ratio of strawberry is relatively low, that is mainly restricted by evaluation system and deep processing technology. In this paper will provide scientific and efficient of evaluation systems and evaluation method for our country the strawberry in processing varieties of resource utilization and breeding, at the same time in order to screen for quick-frozen processing of raw materials, provide theoretical basis for deep processing of quick-frozen strawberries, the establishment of a comprehensive quality evaluation system for development of strawberry processing industry has important guiding significance.In this study, twelve strawberry cultivars from Liaoning Province in China are chosen as the raw materials, and then processed by individual quick freezing. Fourteen quality parameters of strawberry raw material and twelve parameters of IQF strawberry are analyzed and determined by principal component analysis and correlation analysis, purpose is to screen the core index of strawberry raw materials and quick-frozen strawberry quality.The data is standardized in order to remove the impact of different units, application of analytic hierarchy process (AHP) evaluation for establishing quality index model. The combination of standardization of strawberry material index with comprehensive value of quick-frozen strawberries, and data analysis with IQF values by stepwise regression analysis in order to establish the IQF strawberry quality and raw materials associated model. The purpose is to provides scientific basis and technical support for the strawberry industry and strawberry quality assessment.Through the study of raw materials and the quality of the quick-frozen strawberries strawberry, the conclusions can be summarized as follows:(1) The strawberry raw material quality analysis results show that the quality indexes of 14 in different degree of coefficient of variation among different varieties. Coefficient of variation of L value, crude protein, soluble solids and moisture content are less than 10%, the result shows that four indexes was not significant difference between the varieties. The rest of the ten indicators of variation coefficient is more than 10%, significant difference are found in each quality index data. The results of strawberry material index correlation coefficient analysis showed that there were 105 correlation coefficient, including the 0.05 level has seven significant correlation, four correlation at 0.01 level. The vast majority of indicators had no significant correlation.(2) Six important quality evaluation indicators of strawberry raw material:a value, sugar-acid ratio, anthocyanins, total phenols, Vc and hardness. Analytic hierarchy process (AHP) is used to analyze the core index weights given, in order to set up comprehensive evaluation model of strawberry raw materials:Y= 0.311358×a value+0.311358xsugar-acid ratio+0.167618xhardness+0.06836xanthocyanins+0.057249xtotalphenolx0.084058xVitamin C.Sensory analysis is taken on twelve varieties strawberry raw material. The linear correlation coefficient of 0.9248.(3) IQF strawberry quality index shows that quality indexes of total phenols, soluble sugar and drip loss have a low coefficient of variation (<10%), discrete degree is small. The remaining eight quality index variation coefficients are more than 10%. The correlations of IQF strawberry 12 index shows that 3 correlation coefficient at 0.01 level and 5 correlation coefficient at 0.05 level.(4) Seven important quality evaluation indicators of IQF strawberry:Sugar-acid ratio, a value of fruit color, anthocyanins, total phenols, Vc, hardness and drip loss. Analytic hierarchy process (AHP) is used to analyze the core index weights given, in order to set up comprehensive evaluation model of IQF strawberry:Y= 0.288285 x sugar-acid ratio+0.288285 x a value+0.092462 x anthocyanins+ 0.092083 x total phenols+0.150529 x hardness+0.032088 x drip loss.Sensory analysis is taken on twelve varieties IQF strawberry. The linear correlation coefficient of 0.9106.(5) Quality characteristics of strawberry raw materials and seven core indexes of IQF strawberry have a significant correlation.12 varieties IQF strawberry are chose for establishing IQF strawberry quality and raw materials associated model:Y= 0.851-0.664 x totao phenols-0.497 x sugar-acid ratio+0.295 x moisture content +0.160 x hardness.(6) Quick-frozen effect on aroma:99 and akihime strawberry aldehyde change is most obvious, quick-frozen makes 99 strawberry aldehydes increased obviously and Akihime strawberry aldehyde down significantly. The alcohols of R7,99, and akihime are significantly affected by quick frozen, R7 and akihime are increased obviously,99 strawberry alcohols decreased obviously. Strawberry varieties of All-star, Ever bearers, R7 and Akihime ketone after quick-frozen strawberries have grown significantly, frozen is not significant effects on 99 strawberry ketone.(7) The esters better preserved after IQF processing. Strawberries processed by quick-frozen for five months of ester aroma composition is significantly higher than slow frozen strawberries at the same period. Freezing storage process, the LOX activity deactivation degree of quick-frozen strawberries lower than slow frozen, no significant difference between them, quick-frozen and slow-frozen in the process of the AAT and ADH activity and gene expression keep lower level, may be associated with the ester aroma of strawberry aroma becomes weak.更多还原