Measuring texture quality of mulberry fruit using a texture analyser

Abstract:【Objective】Mulberry fruits taste good, which is largely influenced by texture. Texture param- eters including hardness, adhesiveness, cohesiveness, springiness, gumminess and chewiness, have been recorded in many fruits by a texture analyser. However, the texture profile studies on mulberry fruit are limited. By comparing with different probes, testing speed, maximum inductive element, mini- mum inductive element and shape variables, a unified optimum method was established for detecting the texture quality of mulberry fruit at different maturity.【Methods】For probe selection, the texture of JiSang 501 (An Shen) fruits during ripening was detected with a TMS-Pro/Touch texture analyser. In texture profile analysis (TPA) mode, three different probes, named P/2, P/5 and P/10 with 2, 5 and 10 mm in diameter, respectively, were used to evaluate the texture quality. The test speed, pretest speed, post-test speed, deformation, maximum sensing element, minimum sensing element and data acquisi- tion rate were 1 mm·s-1, 0.5 mm·s-1, 0.5 mm·s-1, 40%, 500 N, 0.3 N and 9600, respectively. Fresh fruit samples were placed at the appropriate position on the object stage. The surface at the middle part was used as the test platform.【Results】(1) Among three probes, the stress area of P/2 probe and the index of mulberry texture quality was the smallest, and the texture curve exhibited drastic changes. Hence, the coincidence between them was not good. While the stress area of P/10 probe was large, and the error of texture index tested among samples was too large. The indexes detected by the P/2 and P/10 probe could not adequately evaluate the pericarp texture. On the contrary, the consistency of texture index measured by P/5 probe was better. Thus, the P/5 probe was more suitable for analyzing the texture quali- ty of mulberry fruit than other two probes. (2) Correlation analysis among all texture parameters showed that mulberry hardness was significantly (positively) correlated with springiness and chewiness. Cohesiveness was very significantly (positively) correlated with springiness and chewiness, but the cor- relation between adhensiveness and other parameters was not significant. It was suggested that the TPA parameters (hardness, cohesiveness, springiness and chewiness) can be used to characterize the fruit quality. (3) In the orthogonal test and range analysis, the deformation was the most important influenc- ing factor. The optimal parameters of deformation, maximum sensing element, test speed, and minimum sensing element were 50% , 400 N, 60 mm · min- 1 and 0.3 N, respectively.【Conclusion】The surface at the middle part was used as the test platform. The obtained parameters including hardness, adhesiveness, springiness, cohesiveness, chewiness and gumminess can accurately reflect the texture quality of fresh mulberry fruits.