Evaluation of flesh texture of seven pear varieties at different ripening stages

Abstract: 【Objective】The texture of the flesh is one of the important quality indicators the fruits, and is closely related to tissue state, taste and flavor of the fruits, which is often use to evaluate fruit the maturity, storability and shelf life. There are great differences in flesh texture between different pear varieties, and the changes in fruit components are closely related to the maturity of the fruit, which directly affects the edible quality, storability and transportation quality and commodity value of the fruit. This study analyzed the dynamic variations of flesh texture parameters of seven pear fruits with ripening, texture types during different shelf life at room temperature, and differences in flesh texture traits among different pear varieties.【Methods】In this experiment, three crispy pear varieties such as Huailai Dayali (Pyrus bretschneideri Rehd.), Kuerlexiangli pear (P. sinkiangensis Yu.) and Yali (P. bretschneideri Rehd.), and four soft flesh pear varieties such as Jingbaili (P. ussuriensis Maxim.), Nanguoli (P. ussuriensis Maxim.), Wujiuxiang (P. bretschneideri × P. communis) and Jeanne d’Are (P. communis L.) wereused as test materials, and the fruits with good fruit shape and consistent ripeness were collected on September 10, September 20 and September 30, and placed in the laboratory, and the harvested fruits were sampled and tested at the 7, 14 and 21 days of the postharvest shelf life. An electronic balance and a PR- 101α refractometer (Japan ATAGO company) were used to measure the weight of pear fruit and content of soluble solids, respectively, and six texture parameters including fracture, firmness, cohesiveness, springiness, gumminess, and chewiness of the flesh were determined by a Texture Profile Analysis (TPA) food physical property analyzer, and correlation analysis of texture parameters was carried out. In the TPA test, the fruit is cut longitudinally into two halves along the pear fruit stalk. Each half of the fruit was sampled with a hole punch with an inner diameter of 10 mm using a small cylinder, and the tissue column with a height of 9 mm was placed on the plate of the texture analyzer. TPA test was carried out with a cylindrical probe with a diameter of 75 mm. Each random sample of 10 fruit was used for the determination of texture parameters, and the test for each fruit was repeated 4 times.【Results】The average weight per fruit of the seven pear varieties gradually increased with fruit ripening, and the change trend of soluble solids varied among different varieties and flesh texture types. Flesh fracture, firmness, cohesiveness, springiness, gumminess, and chewiness of the crispy pears in different harvest periods varied within a small range and gradually decreased with the extension of shelf life, among which the flesh texture parameter values of Yali were always at a high level. The variation in flesh texture parameters of soft flesh pears, Jingbai pear, Nanguo pear, Wujiu Xiang and Jeanne d’Are was greater than that of the crispy pears. Among fracture, firmness, springiness, gumminess and chewiness, the five texture parameters of the flesh of Jingbai pear and Nanguo pear were at a high level at the 7th day of the shelf life, and the value of the texture parameters had decreased significantly by the 14th day of the shelf life, and changed slightly by the 21 d of the shelf. The cohesiveness changed less during the shelf period. Flesh fracture, firmness, gumminess and chewiness of Wujiuxiang and Jeanne d’Are fruits harvested on September 10 were relatively high at the 7th day of the shelf life and had decreased sharply by the 14th day of the shelf life, and then remained basically stable thereafter. However, the four texture parameters of Wujiuxiang and Jeanne d’Are fruits harvested on September 20 and September 30 remained basically unchanged and were at a low level with the extension of the shelf life. In addition, with the extension of shelf life, the cohesiveness of Wujiuxiang changed in a small range; the parameter value of springiness gradually decreased. The cohesiveness of Jeanne d’Are gradually increased, and springiness gradually decreased. The correlation analysis showed that there was a significant positive correlation between fracture, firmness, springiness, gumminess and chewiness, indicating that one or more of these five texture parameters could be used to distinguish the differences in flesh texture of the seven pear varieties and cohesiveness was significantly positively correlated with firmness and chewiness, and extremely positively correlated with gumminess.【Conclusion】The texture- related indexes of flesh such as fracture, firmness, cohesiveness, springiness, gumminess and chewiness obtained by the texture analyzer of TPA method can better reflect the change in texture of pear fruits with different ripeness during shelf life and can be used to characterize the texture of different pear varieties and determine harvest period of pear varieties.