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In this research, a novel protease from Ambarella (Spondias cytherea) was identified as a new potential halal meat tenderizer. Optimization of protease extraction by response surface methodology has found the optimized variables at pH 8.22, 4.95% of TX‐100, 6.80 mM of 2‐mercaptoethanol, and 1.71 min of mixing time at 12.37 U/g of protease activity. The overall model was significant (p < .05) with an R2 value of 0.9885. Verification test results (Tukey's test) showed that no significant difference between the expected and experimental protease activity value (98%). The enzyme was stable at pH 8.0–10.0 and temperature 50–60°C. Incubation of enzyme with organic solvents showed higher activity in hydrophobic than hydrophilic phases. In addition, prolonged storage time of enzyme decreased the activity by 32%. Protein bands of muscle proteins and firmness of muscle samples were reduced upon protease treatment due to breaking of tissue fibers and loosening of myofibrils. Practical applications Treatment by exogenous proteases is one of the various tenderization techniques used in the meat industry to improve meat tenderness. Myofibrillar and connective tissue proteins which cause toughness in meat were effectively hydrolyzed by the protease enzymes. The results of the present study should be useful to the meat industry for discovering new source of plant protease which is able to overcome the shortcoming of animal and microbial proteases as meat tenderizer.

Kenaf (Hibiscus cannabinus L.) seed is rich in protein, fat, fiber, and other essential nutrients. Kenaf seed comprises of high protein (22–31%) and oil (22–25%) contents which suggested its high potential food application. This chapter discusses the potential and early development of kenaf-based plant-milk and tofu. The step-by-step processes involved in preparation of kenaf-based milk and kenaf-based tofu at laboratory-scale are illustrated. Soaking conditions (temperature and time) of kenaf seed as pretreatment in preparation of kenaf seed milk were highlighted. Hydration of kenaf seed were found to be faster at elevated temperature, however higher soaking temperature and prolonged soaking time causes some losses of protein (%) and solid content (%) which are unfavorable for production of highly nutritious plant-based milk. Furthermore, in preparation of kenaf-based tofu, soaking temperature of seed also affected the properties of the tofu. As the soaking temperature was increased from 25–65°C, the yield, hardness, and chewiness of kenaf tofu decreased. It was recommended that soaking of kenaf seed at 25°C and the use of aluminum potassium salt at 1.00 g% as coagulant produces kenaf-based tofu with optimum quality.

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Hydration of kenaf seed was studied at 25, 35 45, 55 and 65 °C by the method of weight gain until equilibrium was achieved along with the physicochemical properties of the seed. The results showed that the kenaf seed had a small dimension and brownish surface color. Water absorbed during soaking was a function of soaking time and temperature. Soaking at higher temperatures increased the hydration rate constant and decreased the soaking time needed to reach equilibrium. Sigmoidal, Peleg and Page models effectively described the hydration characteristics of the seed under the soaking temperatures. The half-saturation time; τ, Peleg' s rate constant; K1 and Page rate constant K3 decreased from 199.78-32.97 min, 2.55-0.47 min/% and 3.14-2.74 min/%, respectively, while the sigmoidal rate constant; K increased from 0.85-6.83 min-1 with an increase in soaking temperature from 25-65 °C. The rate of water absorption of the seed at a higher temperature was faster. The temperature dependence of K was explained by the Arrhenius equation, from which activation energy of 71.31 KJ/mol was obtained.