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Grey relational analysis (GRA), an approach totally different from traditional statistical analysis used to calculate the relational grade between two sequence data, was applied to classify dried roselle (Hibiscus sabdariffa L.). In this study, 49 groups of roselle calyces representing five treatments – (1) frozen at −20C; (2) cold‐air‐dried at 25C, or (3) hot‐air‐dried at 50C; (4) 75C; or (5) 85C – were investigated. Five calyces from each group of treated roselle calyces were selected at random as reference samples and were built into the database. The rest of the treated roselle calyces were selected as test calyces to validate the feasibility of the developed Grey identification system. A GRA calculation procedure is demonstrated step‐by‐step and results are compared with the results of principal component analysis (PCA). PCA exhibited no distinguishable cluster pattern on the PCA plot of roselle calyces hot‐air‐dried at 50C or 75C. The GRA grades identified and classified all undried and dried roselle calyces correctly.

The Taguchi method was applied to determine optimum conditions for submerged culture of Monascus spp. fermentation to produce a high yield of monacolin K (also known as lovastain, mevinolin or mevacor). The control factors included carbon, nitrogen, oil, and salt sources and pH values. In the growth phase the optimum culture conditions are 1% whole wheat flour, l% peptone, 0.01% olive oil and 0.01% potassium phosphate and a pH of 5.0 (P < 0.05). In the metabolic phase the optimal culture conditions are 1% whole wheat flour, 1% peptone, 0.01% soybean oil, 0.01% potassium phosphate and a pH of 3.0 (P < 0.001). Using optimal culture conditions in the growth and metabolic phases, the yield of monacolin K in the fermentation process was 151.06 ppm. PRACTICAL APPLICATIONSThe Taguchi method can be employed for all kinds of industries. By using orthogonal arrays, it reduces the number of experimental trials to a practical and effective size. It helps us to optimize manufacturing processes involving multiple factors with different numbers of levels, especially fermentation processes and new food product developments, simultaneously and economically. In this Monascus spp. fermentation process, five factors with four levels need only 16 experimental trials. A set of optimal conditions can be established after a calculation of signal-to-noise ratio and analysis of variance to produce 1 Corresponding author. HO-Hsien Chen,

This research aimed to develop an electrolysis method to generate high-concentration chlorine dioxide (ClO2) for tilapia fillet disinfection. The designed generator produced up to 3500 ppm of ClO2 at up to 99% purity. Tilapia fillets were soaked in a 400 ppm ClO2 solution for 5, 10, and 25 min. Results show that total plate counts of tilapia, respectively, decreased by 5.72 to 3.23, 2.10, and 1.09 log CFU/g. In addition, a 200 ppm ClO2 solution eliminated coliform bacteria and Escherichia coli in 5 min with shaking treatment. Furthermore, ClO2 and trihalomethanes (THMs) residuals on tilapia fillets were analyzed by GC/MS and were nondetectable (GC-MS detection limit was 0.12 ppb). The results conform to Taiwan's environmental protection regulations and act governing food sanitation.