Utilization of the basket press method to extract verjuice

Abstract

In this study, two cylinders were used as the main part of the basket press. Berries were poured into the cylinders and were subjected to compression force. Loading rate, layer height, number of layers, and cylinder diameter were considered operating factors. Force–deformation data were recorded. At the end of each test, the mass of extracted juice was measured. Extraction Yield of Juice (YOP), pomace density, Specific Absorbed Energy by Berries (SAEB), and Efficiency Index of Energy (EIE) were output variables. Analysis of variance and optimization were performed. The operating parameters on YOP and SAEB were effective at a significance level of p-value < .01. Moreover, the EIE was significant under the effect of all inputs at 5%. YOP and SAEB ranged from 23.42 to 43.10% and 192.23 to 255 J kg−1, respectively, for basket 1. The corresponding values for basket 2 were 11.07 to 27.81% and 53.53 to 84.01 J kg−1, respectively. Novelty impact statement The basket press method helps to maintain the quality of the juice because by applying the controlled pressure, the bitter seeds of the unripe grape berries can be prevented from being crushed and the bitterness transferred to the juice. The pressure on the berries was increased to the point that the quality of the extracted verjuice did not decrease. Effects of loading rate, layer height, and the number of layers are significant on the performance and efficiency of the method.