Pulsed Electric Field as a Novel Technology for Fresh Barhi Date Shelf-Life Extension: Process Optimization Using Response Surface Methodology

Abstract

Fresh dates of the Barhi cultivar at the Khalal maturity stage are well known for their pleasant taste, crispy texture, and bright yellow color. One of the primary technical challenges is preserving the initial high-quality fresh Khalal Barhi dates and extending their shelf life for the longest possible period after harvesting and during the marketing process. Resolving this problem would permit the export of high-quality fresh Saudi dates to international markets. Therefore, the main aim of this study is to evaluate the feasibility of utilizing a pulsed electric field as a novel non-thermal postharvest processing technology for preserving the nutritional, microbiological, and physical quality of Barhi dates during storage at different temperatures and durations. To accomplish this goal, a five-factor mixed-level central composite rotating design (CCRD) with a response surface methodology (RSM) model was used to define the best PEF processing conditions and subsequent storage environments. The influence of independent factors, PEF intensity (10, 20, 30, and 40 kV/cm), PEF exposure time (40, 80, 120, and 160 ms), PEF numbers (50, 100, 150, and 200 pulses), storage temperature (1 °C, 5 °C, 15 °C, and 25 °C), and storage time (1 day, 6 days, 11 days, 16 days, and 21 days), on the total soluble solids, firmness, total color changes, total viable count, total phenolic content, DPPH antiradical activity, fructose, and glucose were assessed. The results indicated the optimal conditions of PEF treatment and subsequently storage conditions for conserving the quality and elongating the storability of fresh Barhi dates were: 10.3 kV/cm PEF intensity; 46.73 ms PEF duration; number of PEF, is 169.9 pulses; 18.7 °C storage temperature; and 21 days’ storage time. At the aforementioned optimal conditions, the values of total soluble solids (TSS), firmness, ΔE, total viable count (TVC), total phenolic content (TPC), DPPH antiradical activity, glucose, and fructose were 41.44%, 62.47 newton, 0.1, 0.098 log CFU/g, 1.29 mg GAE/g, 65.95%, 3.45, and 3.44, respectively. These values were comparable to the predicted values (Desirability value = 1), indicating that the applied RSM models were ideal for optimizing the PEF and storage conditions for preserving the quality and prolonging the fresh Barhi dates’ shelf life. Overall, the ideal PEF treatment and storage conditions for sustaining the quality characteristics of Barhi dates during an extended storage time were identified in this study.