School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs, National R&D Center for Aquatic Product Processing, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China.
J Agric Food Chem. 2022 May 4;70(17):5396-5407. doi: 10.1021/acs.jafc.2c00530. Epub 2022 Apr 22.
-l-Lactoyl phenylalanine (-l-lactoyl-Phe) has been identified as a taste-active contributor in many fermented foods. However, its preparation, taste property, and content in foodstuffs are little known to date. In the current study, two preparation technologies of -l-lactoyl-Phe including heating and enzymatic methods were investigated. Other investigations include its taste property and quantification in several fermented foods. The results indicated that the heating preparation and enzymatic preparation only produced -l-lactoyl-Phe instead of -d-lactoyl-Phe in the presence of l-lactate/d-lactate and l-phenylalanine (Phe). A high yield (58.0% ± 0.7%) of -l-lactoyl-Phe was achieved under the following conditions: Phe, lactate, CaO, and water at molar ratios of 1:8:0.3:9 kept at 100 °C for 3 h. With nine enzymes, a maximum yield of 21.2% ± 0.3% was achieved in the aqueous solution under mild operating conditions: 0.18 M Phe, 0.90 M lactate, 5 g/L Debitrase HYW 20, pH 8, and 55 °C for 24 h. The sensory evaluation revealed that -l-lactoyl-Phe in water enhanced the salty and umami intensity. It also enhanced the thickness, mouthfulness, and continuity of salt solution, model broth, and chicken broth, revealing that -l-lactoyl-Phe was a kokumi-active compound. The kokumi thresholds of -l-lactoyl-Phe in these solutions were 50, 50, and 25 mg/L, respectively. -l-Lactoyl-Phe was quantified in traditional Chinese fermented foods as 30.12 ± 0.28 mg/kg in preserved pickles, 14.11 ± 0.14 mg/kg in soybean paste, 4.87 ± 0.16 mg/kg in fermented bean, 0.71 ± 0.11 mg/kg in rice vinegar, and 20.34 ± 0.18 mg/kg in soy sauce. These results revealed the potential of -l-lactoyl-Phe as a taste enhancer, presenting a new opportunity for the food industry.
-l-乳酰苯丙氨酸（-l-乳酰-Phe）已被鉴定为许多发酵食品中具有味觉活性的贡献者。然而，其制备、味觉特性和在食品中的含量至今知之甚少。在本研究中，研究了包括加热和酶法在内的两种-l-乳酰-Phe 的制备技术。其他研究包括其在几种发酵食品中的味觉特性和定量。结果表明，在 l-乳酸盐/d-乳酸盐和 l-苯丙氨酸（Phe）存在的情况下，加热和酶法制备仅产生-l-乳酰-Phe 而不是-d-乳酰-Phe。在以下条件下，-l-乳酰-Phe 的产率达到 58.0%±0.7%：Phe、乳酸盐、CaO 和水的摩尔比为 1:8:0.3:9，在 100°C 下保持 3 小时。使用九种酶，在温和的操作条件下，水溶液中的产率最高可达 21.2%±0.3%：0.18M Phe、0.90M 乳酸盐、5g/L Debitrase HYW 20、pH8 和 55°C 24 小时。感官评价表明，水中的-l-乳酰-Phe 增强了咸味和鲜味强度。它还增强了盐水、模型肉汤和鸡汤的稠度、口感和连续性，表明-l-乳酰-Phe 是一种 kokumi 活性化合物。-l-乳酰-Phe 在这些溶液中的 kokumi 阈值分别为 50、50 和 25mg/L。-l-乳酰-Phe 在传统中国发酵食品中的含量分别为：腌制泡菜 30.12±0.28mg/kg、豆瓣酱 14.11±0.14mg/kg、豆豉 4.87±0.16mg/kg、米醋 0.71±0.11mg/kg、酱油 20.34±0.18mg/kg。这些结果表明-l-乳酰-Phe 具有作为味觉增强剂的潜力，为食品工业提供了新的机会。
