Protein–protein cross-linking and protein-fat interactions in the traditional Lebanese dairy product, Qishta, were investigated. Liquid chromatography coupled to mass spectrometry was used for the detection of lysinoalanine (LAL) and lanthionine (LAN) during the production of Qishta, which is made by heating whole milk in an open shallow vessel for more than 2 h and harvesting the surface aggregates formed. LAL and LAN cross-links were seen in Qishta at concentrations higher than those in milk, indicating their importance in the gel formation and therefore their impact on Qishta texture. Disulphide bridges were also involved in Qishta formation. The amino acid residues (cysteine, serine or threonine) involved in the β-elimination and in dehydroalanine formation were identified. Confocal scanning laser microscopy showed the role of fat globules in the gel structure.

研究了传统黎巴嫩乳制品 Qishta 中的蛋白质-蛋白质交联和蛋白质-脂肪相互作用。将全脂牛奶在敞开的浅容器中加热 2 小时以上，然后收集形成的表面聚集体制成的奇什塔（Qishta）生产过程中，采用液相色谱-质谱联用技术检测赖氨酸丙氨酸 (LAL) 和羊毛硫氨酸 (LAN) . 在 Qishta 中发现 LAL 和 LAN 交联的浓度高于牛奶中的浓度，表明它们在凝胶形成中的重要性以及它们对 Qishta 质地的影响。二硫键也参与了 Qishta 的形成。鉴定了参与β-消除和脱氢丙氨酸形成的氨基酸残基（半胱氨酸、丝氨酸或苏氨酸）。