Bovine milk spiked with seven organophosphorus pesticides, i.e., dimethoate, fenthion, malathion, methyl parathion, monocrotophos, phorate and trichlorphon, was fermented at 42?C with commercial directed vat set (DVS) starters to investigate the degradation kinetics of the pesticides during yoghurt processing. The spiked pesticides were extracted from the prepared samples with an organic solvent and analyzed by gas chromatography after purification. Based on published results that the degradation kinetics of pesticides is first order, the rate constant of degradation and the half live period of the pesticides were calculated. The results indicated that degradation of the pesticides in milk during yoghurt processing were enhanced by one or both starters, except for malathion, and the two commercial DVS starters had different influences on the degradation kinetics of the pesticides.

Bovine lactoferrin hydrolysate (BLH) was prepared with pepsin, fortified with Cu²⁺ (Mn²⁺) 0.64 and 1.28 (0.28 and 0.56) mg/g protein, and then assessed for their activity against human gastric cancer BGC-823 cells. BLH and the four fortified BLH products dose- and time-dependently had growth inhibition on the cells in both short- and long-time experiments. These samples at dose level of 25 mg/mL could stop cell-cycle progression at the G0/G1-phase, damage mitochondrial membrane, and induce cell apoptosis. In total, the fortified BLH products had higher activities in the cells than BLH alone. Moreover, higher Cu/Mn fortification level brought higher effects, and Mn was more effective than Cu to increase these effects. In the treated cells, the apoptosis-related proteins such as Bad, Bax, p53, cytochrome c, caspase-3, and caspase-9 were up-regulated, while Bcl-2 was down-regulated. Caspase-3 activation was also evidenced using a caspase-3 inhibitor, z-VAD-fmk. Thus, Cu- and especially Mn-fortification of BLH brought health benefits such as increased anti-cancer activity in the BGC-823 cells via activating the apoptosis-related proteins to induce cell apoptosis.

Casein hydrolysates (CH) were prepared using papain and modified by the plastein reaction (CH-P) in the presence of extrinsic phenylalanine (CH-P-Phe) or tryptophan (CH-P-Trp). The in vitro protective activity of CH and its modified products against ethanol-induced damage in HHL-5 cells was investigated. The results showed that the modification by the plastein reaction reduced the amino group content of CH. However, the modification by the plastein reaction in the presence of extrinsic amino acids could enhance the antioxidant, proliferative, cell cycle arresting, and anti-apoptosis activity of CH. Biological activities of CH and its modified products in the HHL-5 cells varied depending on the hydrolysate concentration (1, 2, and 3 mg/mL) and treatment time (24, 48, and 72 h). Generally, higher biological activities were found after cell treatment with CH or its modified products at concentration of 2 mg/mL for 48 h compared to other treatments. In addition, CH modified in the presence of tryptophan (CH-P-Trp) showed higher biological activity than that modified in the presence of phenylalanine (CH-P-Phe). Based on the obtained results, it can be concluded that casein hydrolysates with enhanced biological activity and potential health benefits can be produced by papain and the plastein reaction with the incorporation of extrinsic amino acids.

Lactoferrin is an interesting bioactive protein in milk and can interact with various metal ions of trace elements such as copper, iron, manganese, and others. In this study, a lactoferrin hydrolysate (LFH) was generated from commercial bovine lactoferrin by protease pepsin, fortified with Cu²⁺ (or Mn²⁺) at two levels of 0.64 and 1.28 (or 0.28 and 0.56) mg/g protein, respectively, and then measured for the resultant bioactivity changes in the well-differentiated human gastric cancer AGS cells. The assaying results indicated that the LFH and Cu/Mn-fortified products had long-term anti-proliferation on the cells, while the treated cells showed DNA fragmentation and increased apoptotic cell proportions. Regarding the control cells, the cells treated with the LFH and especially Cu/Mn-fortified LFH had remarkably up-regulated mRNA expression of caspase-3 and Bax by respective 1.21–3.23 and 2.23–2.83 folds, together with down-regulated mRNA expression Bcl-2 by 0.88–0.96 folds. Moreover, Western-blot assaying results also indicated that the cells exposed to the LFH and Cu/Mn-fortified LFH (especially Mn at higher level) for 24 h had an enhanced caspase-3 expression and increased ratio of Bax/Bcl-2. It can thus be concluded that the used Cu/Mn-addition to the LFH may lead to increased bioactivity in the AGS cells; to be more specific, the two metal ions at the used addition levels could endow LFH with a higher ability to cause cell apoptosis by activating caspase-3 and increasing the Bax/Bcl-2 ratio.

In the present study, carrot juice prepared was added into skimmed milk before fermentation to produce 10% and 20% (w/w) carrot-fortified skim milk. The influence of carrot juice on the lactic acid content, chemical composition, syneresis, texture, rheology property, and microstructure was evaluated along with a potential of carrot juice as an ingredient with rich dietary fiber and a firm structure with interaction of milk protein and a complex matrix under acidification. The results showed that the pH of yoghurt significantly ( ) reduced with carrot juice addition, minimizing fermentation time by nearly 1 h and brought about an enhanced postacidification during the storage period while titratable acidity increased. Moreover, carrot juice addition had no significant effect on ferric reducing power and phenolic content ( ). With 10% and 20% level carrot juice added, the total phenolic content (mg GAEkg⁻¹) increased (37.86 and 38.92, respectively) compared with control (36.91) ( ). Besides, the addition of carrot juice also showed reduced syneresis, increased apparent viscosity and viscoelastic modulus, stable texture, and a refined microstructure. Overall, this study confirmed that carrot juice has a potential as natural and nutrient composition to obtain firm and compact texture and enhance the beneficial quality of yoghurt.

Partially substituting other proteins in soy-protein-based products is an effective method to meet nutritional and application requirements. However, the emulsifying properties of soybean protein isolates (SPI) when partially substituted with zein hydrolysates (ZH) remain unknown. In the present work, protein blend (0 h-SPI/ZH) from SPI and ZH with a ratio of 3.5: 1 (w/w) was treated by transglutaminase (TGase) for 0, 0.5, 1.0, and 1.5 h, respectively. SDS-PAGE analysis results indicate protein polymers were generated in SPI/ZH conjugates. Emulsifying activity of the conjugates (1.5 h-SPI/ZH) was significantly increased from 23.69 to 28.13 m² g⁻¹ in comparison with SPI, and there was no statistically significant difference (p < 0.05) in emulsion stability. The apparent viscosity, surface hydrophobicity of the SPI/ZH conjugates were significantly increased. Emulsion droplet size and zeta potential stabilized by 1.5 h-SPI/ZH were also increased; the values were 64.73 to 80.79 r.nm and −21.8 to −29.9 mV, respectively. CLSM results indicate that 1.5 h-SPI/ZH conjugates stabilized the emulsion and had a thicker adsorption layer. Overall, high values of negative zeta potential and suitable molecular weight distribution of the SPI/ZH conjugates might be responsible for the improved emulsifying property. This study provides insights for the preparation of soy-protein-based products as a promising food emulsifier.