Design and Validation of Automated Sensor-Based Artificial Ripening System Combined with Ultrasound Pretreatment for Date Fruits

Abstract

Climate change affects fruit crops’ growth and development by delaying fruit ripening, reducing color development, and lowering fruit quality and yield. The irregular date palm fruit ripening in the past few years is assumed to be related to climatic change. The current study aimed to design and validate an automated sensor-based artificial ripening system (S-BARS) combined with ultrasound pretreatment for artificial ripening date fruits cv. Khalas. A sensor-based control system was constructed to allow continuous real-time recording and control over the process variables. The impact of processing variables, i.e., the artificial ripening temperature (ART-temp) and relative humidity (ART-RH) using the designed S-BARS combined with ultrasound pretreatment variables, i.e., time (USP-Time) and temperature (USP-Temp) on the required time for fruit ripening (RT), the percentage of ripened fruits (PORF), the percentage of damaged fruits (PODF), and the electrical energy consumption (EEC) were investigated. The quadratic predictive models were developed using the Box–Behnken Design (B-BD) to predict the RT, PORF, PODF, and EEC experimentally via Response Surface Methodology(RSM). Design Expert software (Version 13) was used for modeling and graphically analyzing the acquired data. The artificial ripening parameter values were determined by solving the regression equations and analyzing the 3D response surface plots. All parameters were simultaneously optimized by RSM using the desirability function. The Mean Absolute Percentage Error (MAPE) and the Root Mean Square Error (RMSE) between the predicted and actual experimental values were used to evaluate the developed models. The physicochemical properties of the ripened fruit were assessed under the optimization criteria. The results indicated that the pretreated unripe date fruits with 40 kHz ultrasound frequency, 110 W power, and USP-Temp of 32.49 °C for 32.03 min USP-Time under 60 °C ART-Temp and 59.98% ART-RH achieved the best results. The designed S-BARS precisely controlled the temperature and relative humidity at the target setpoints. The ultrasound pretreatment improved the color and density of the artificially ripened date fruits, decreased the RT and EEC, and increased the PORF without negatively affecting the studied fruit quality attributes. The developed models could effectively predict the RT, PORF, PODF, and EEC. The designed S-BARS combined with ultrasound pretreatment is an efficient approach for high-quality ripening date fruits.