Abstract:【Objective】Mastication quality is one of the important qualities of citrus fruits, significantly affecting the consumer's taste experience. However, previous researches of citrus fruit qualities mainly focus on the sugar and acid, the researches of citrus fruit mastication are still very limited. Thus, the objective of this study is to explore the differences in mastication quality of mandarins in Hubei Province and its main influencing factors, which will further provides a theoretical foundation for the high-quality cultivation of mandarins.【Methods】Samples of early-maturing and mid-early maturing mandarins were selected from different orchards in Hubei Province. Fully ripe fruits were collected at the appropriate harvest time, selecting 45 fruits of medium size from different parts of the tree without obvious damage for the experiment. The fruits were transported to the laboratory on the day of harvest for the determination of physiological and biochemical indicators. The samples were separated into peel and pulp, with a portion of the pulp frozen in liquid nitrogen and stored at -80 ℃ for the determination of cellulose and pectin content. The remaining pulp samples were dried in an oven at 120 ℃ to a constant weight, ground, and then sieved through a 60-mesh screen. The sieved samples were placed in sealed bags and stored at room temperature in a desiccator for later determination of lignin content. A comprehensive evaluation of the mastication quality of mandarins was conducted through sensory assessment and texture analysis instruments. Furthermore, the main factors influencing the mastication quality of mandarin fruits were preliminarily analyzed through correlation analysis, multiple linear regression analysis, and principal component analysis.【Results】The individual fruit weight of early-maturing mandarins from different production areas varies significantly, ranging from 54.00 to 129.33g, with peel thickness ranging from 2.15 to 4.32mm. The transverse diameter ranges from 5.03 to 7.03cm, and the longitudinal diameter from 3.73 to 5.82cm. The internal quality differences are pronounced, with soluble solids content ranging between 8.63 and 13.7%, averaging 10.56%; titratable acidity content between 0.33 and 0.84, vitamin C content between 15.92 and 39.81 mg/100g, and the sugar-acid ratio between 10.33 and 31.31, with an average value of 16.40. The individual fruit weight of mid-early maturing mandarins from different production areas ranging from 68.17 to 169.67g, with peel thickness ranging from 0.83 to 4.14mm. The transverse diameter ranges from 5.56 to 8.1cm, and the longitudinal diameter from 4.18 to 6.64cm.The content of soluble solids in the fruits of mid-early maturing mandarins ranges from 8.47 to 14.3%, with an average of 11.53; the titratable acidity content ranges from 0.3 to 1.09, vitamin C content from 17.5 to 46.23 mg/100g, and the sugar-acid ratio from 10.33 to 31.31, with an average value of 18.30.There were significant differences in the quality of mandarins from different production areas in Hubei, with the mid-early maturing mandarins generally exhibiting better quality than the early-maturing mandarins. The mid-early maturing varieties in 2022 exhibited characteristics of high sugar and high acidity. The mastication score of early-maturing mandarins ranges from 4.6 to 8.55, with an average score of 6.38. Puncture force ranges from 97.09 g to 302.5 g, shear force from 896.43 g to 2683.33 g, lignin content from 37.05 to 209.18 mg/g, cellulose content from 10.1 to 20.15 mg/g, and pectin content from 7.54 to 24.79 mg/g. Specifically, sample No. 9 scored the lowest in mastication at 4.6, with the highest puncture and shear forces, as well as the highest lignin content.The mastication score of mid-early maturing mandarins ranges from 3.38 to 8.24, with an average of 6.01. Puncture force ranges between 78.45 g and 239.38 g, shear force between 848.58 g and 3926.24 g, lignin content from 66.48 to 208.9 mg/g, cellulose content from 10.1 to 20.15 mg/g, and pectin content from 7.54 to 24.79 mg/g. Specifically, sample No. 55 scored the highest in mastication at 8.24; sample No. 29 scored the lowest at 3.38, with the highest puncture and shear forces.Correlation analysis indicated that the transverse diameter, longitudinal diameter, and individual fruit weight were significantly positively correlated with each other and negatively correlated with TSS and VC content, but positively correlated with shear force and lignin content. The mastication score was significantly negatively correlated with TA, shear force, and puncture force, while shear force was significantly positively correlated with puncture force. Lignin content was significantly positively correlated with peel thickness and shear force, and negatively correlated with SAR. Pectin content showed a significant positive correlation with transverse diameter, TA, and cellulose content. A predictive model for the sensory comprehensive evaluation was constructed using multiple linear regression analysis, including TSS, puncture force, lignin content, and pectin content, all of statistical significance: Y (mastication score) = 5.875 + 0.108X (TSS) - 0.007X (puncture force) - 0.007X (lignin content) + 0.044X (pectin content). The comprehensive taste prediction score of this model is essentially consistent with the actual comprehensive taste score.【Conclusion】The comprehensive score prediction model established based on regression analysis facilitates the comprehensive evaluation of the sensory quality of mandarin fruits. The indices of texture characteristics and physicochemical components, serving as objective methods, can effectively compensate for the subjective shortcomings of sensory analysis and can be applied to the quality evaluation of mandarins in Hubei Province.
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