Hair waste in large amount is produced in India from temples and saloons, India alone exported approximately 1 million kg of hair in 2010. Incineration and degradation of waste human hair leads to environmental concerns. The hydrothermal process is a conventional method for the production of hair hydrolysate. The hydrothermal process is carried out at a very high temperature and pressure, which causes the degradation of heat-sensitive essential amino acids, thereby depleting the nutritional value. This work deals with alkaline hydrolysis of human hair using acoustic and hydrodynamic cavitation, and comparison with the conventional method. The optimal operating conditions for highest efficiency was observed, for the hydrolysis of 1 g of sample hairs in 100 mL of solution, at 4:1 (KOH: hair) ratio, soaking time of 24 h, the ultrasonic power density of 600 W dm⁻³ (20 KHz frequency and input power 200 W) or hydrodynamic cavitation inlet pressure of 4 or 7 bars. Cavitation results in rupture of disulfide linkages in proteins and mechanical effects lead to cleavage of several hydrogen bonds breaking the keratin sheet structure in hair. Breakdown of bonds leads to a decrease in viscosity of the solution. 10% and 6% reduction in viscosity is obtained at optimal conditions for ultrasonic and hydrodynamic cavitation treatment, respectively. FTIR analysis of produced hair hydrolysate confirmed that the disulfide bonds in hair proteins are broken down during cavitation. The amino acid of hair hydrolysate, prepared using cavitation, has a relatively higher digestibility and nutritional value due to the enhancement of amino-acid content, confirmed using amino acid analysis. Cavitation assisted hair hydrolysate has a potential application in agricultural engineering as a fertilizer for improvement of the quality of the soil and land. Cavitation based hair hydrolysate can also be used as an environmentally friendly and economical source of essential amino acids and digestibles for animal or poultry feed.

印度的寺庙和沙龙会产生大量的头发废料，仅印度在 2010 年就出口了大约 100 万公斤的头发。人发的焚烧和降解会导致环境问题。水热法是生产头发水解物的常规方法。水热过程是在非常高的温度和压力下进行的，这会导致对热敏感的必需氨基酸降解，从而耗尽营养价值。这项工作使用声学和流体动力学空化处理人类头发的碱性水解，并与传统方法进行比较。观察到最高效率的最佳操作条件，1 g 样品毛发在 100 mL 溶液中以 4:1（KOH:毛发）的比例水解，浸泡时间为 24 h，^-3（20 KHz 频率和 200 W 输入功率）或 4 或 7 巴的流体动力空化入口压力。空化导致蛋白质中的二硫键断裂，机械效应导致几个氢键断裂，从而破坏了头发中的角蛋白片结构。键的破坏导致溶液粘度的降低。在超声波和流体动力空化处理的最佳条件下，粘度分别降低了 10% 和 6%。产生的头发水解物的 FTIR 分析证实，头发蛋白质中的二硫键在空化过程中被破坏。使用空化法制备的头发水解液的氨基酸由于氨基酸含量的提高而具有相对较高的消化率和营养价值，经氨基酸分析证实。空化辅助毛发水解物在农业工程中作为改善土壤和土地质量的肥料具有潜在应用。基于空化的毛发水解物也可用作动物或家禽饲料的必需氨基酸和可消化物的环保且经济的来源。