Effect of micro wet milling process on particle sizes, antioxidants, organic acids, and specific phenolic compounds of whole sea buckthorn ( Hippophae rhamnoides L.) juices

This research applied the micro wet milling (MWM) process to develop zero waste, whole sea buckthorn (SBT) juice with pulp and seeds. The optimum MWM operational conditions of feeding rate at 10 ml/min, a rotational speed at 50 rpm, and an adjusted gap between the two millstones by pressed of 43.03 kN were achieved along with a higher yield of minimal particle sizes (D50 of 10.4 µm) of the juice. The MWM SBT juice showed better color, smaller particle size, significantly higher antioxidant properties, and total phenolics in comparison to the mixer milled and commercial SBT juice. HPLC analysis of SBT juice revealed that higher amounts of low molecular weight organic acids and phenolic compounds were found in the MWM SBT juice than commercial SBT juice. The microbiological analysis showed that the initial total viable count of MWM SBT juice was within the permissible limit of standard. Practical applications During the production of SBT juice, an immense amount of pomace, consisting of pulp and seeds, is discarded although it has a high antioxidant value. In our study, the zero‐waste processing method of whole SBT juice using the MWM system was developed. The MWM was successful in producing SBT juice with scaled‐down particle sizes. As a result, higher values of ascorbic acid, total flavonoid content, total phenolic content, and antioxidant activity than those of commercial SBT juice were found in the MWM SBT juice. MWM can be used to minimize the losses of heat‐sensitive bioactive compounds during the processing of berries and also provide fiber‐enriched juice. We concluded that the MWM process demonstrated excellent potential for the processing of whole SBT fruit juice in the food industry.