市售盐凝豆腐品质特性指标分析与评价模型的建立

Analysis of quality characteristic index and establishment of evaluation model of salt coagulated tofu

为建立全面客观的豆腐综合品质评价模型,对市售盐凝豆腐的感官品质、质构特性及水分状态进行了测定及分析,利用主成分分析法,建立了基于18个品质指标的豆腐品质评价模型。结果表明:不同豆腐样本间感官指标、横向弛豫时间、峰占比、质构指标(除弹性外)均存在显著差异;豆腐质构指标与感官硬度、口感、颜色和总体接受度均显著相关,横向弛豫时间与感官硬度、口感和颜色显著相关,峰占比与感官硬度和口感存在显著相关性;利用主成分分析提取了前3个主成分,其累计贡献率达到81.32%,其中主成分1主要代表了感官硬度、质构硬度、胶着性和咀嚼性,主成分2主要代表了回复性和感官弹性,主成分3主要代表了总体接受度和感官弹性;豆腐凝胶体系中不易流动水和游离水的弛豫时间、感官硬度、口感、质构弹性和回复性指标对豆腐品质贡献较大。通过测定18个豆腐品质指标,可以有效评估不同盐凝豆腐的综合品质,比较其品质差异,为客观评价市售盐凝豆腐提供了理论依据和方法。

In order to establish a comprehensive and objective quality evaluation model,13 kinds of salt coagulated tofu from large chain supermarkets,direct shopping stores and small retail stores were used as raw materials,and their sensory hardness,flavor,taste,color,sensory springiness,overall acceptability,texture hardness,texture springiness,cohesiveness,gumminess,chewiness,resilience and moisture state(water relaxation time and proportion)were measured.Single factor analysis of variance was used for multiple comparisons of each indexes,and bivariate test was used to analyze the correlation between sensory evaluation and instrument evaluation.Finally,a tofu quality evaluation model based on 18 quality indexes was established using principal component analysis(PCA).The results showed that there were significant differences in flavor,color,taste,overall acceptance,texture hardness,cohesiveness,gumminess,chewiness,resilience,relaxation time and peak ratio(except the ratio of bound water peak)among gypsum tofu samples.There were significant differences in quality indexes(except sensory springiness)among brine tofu samples.Tofu texture index was significantly correlated with sensory hardness,taste,color and overall acceptability,but was not significantly correlated with flavor and color.And T 2 relaxation time was significantly correlated with sensory hardness,taste,and color.Meanwhile,the peak ratio was positively correlated with sensory hardness and taste.The results showed that the quality of tofu cannot be evaluated by a certain index,but should be evaluated comprehensively by combining sensory index and instrument index.Through principal component analysis,the first three principal components were extracted,and the total variance contribution rate was 81.36%,which can reasonably reflect most qualities of tofu quality.PC1 integrated the information of sensory hardness,texture hardness,gumminess,and chewiness,and PC2 integrated the information of resilience and sensory springiness,and PC3 integrated the overall acceptability and sensory springiness.After further processing with principal component analysis,the evaluation model of tofu quality was established.The relaxation time of immobile and free water,sensory hardness,taste,texture springiness and resilience in the tofu gel system greatly contributed to the quality of tofu.Using the evaluation model,the tofu quality score of tofu can be calculated.The higher the score,the better the quality of tofu.Therefore,brine tofu has better sensory hardness,texture hardness,gumminess and chewiness,while gypsum tofu has higher scores in taste,relaxation time of immobile,and free water.This study provides a theoretical basis and method for the objective evaluation of salt-induced tofu sold in the market.