Peeling of gingers as evaluated by image analysis techniques: A study for pickled ginger process

This paper applied chemical and enzymatic peeling techniques to enhance the efficiency of ginger peeling process. Gingers were peeled using different chemical and enzymatic peeling conditions before being washed by ginger washer/peeler. The efficiency of the peeling process was evaluated using image analysis techniques. It was found that the optimum condition for chemical peeling of gingers was soaking in NaOH solution (1 g/100 g water) at 80°C for 60 s. The yield obtained was 87.4% by weight. Image analysis showed that the average unpeeled area of gingers was 8.73%. It was found that commercially available fruit peeling enzymes had the potential to be used in ginger peeling. The best yield obtained from enzymatic peeling was 90.57% by weight. It also reduced the average unpeeled areas to 1.20%. Enzymatic peeling enhanced the efficiency of the peeling by removing the peels of the areas that could not be reached by chemical peeling. Pickled gingers produced from experimentally peeled gingers provided lower pH, higher protein content and darker color when compared to those made from hand peeled gingers.