Oil Migration in Chocolate–Peanut Butter Paste Confectionery as a Function of Chocolate Formulation

ABSTRACT:  Migration of oil from high oil content filling to the chocolate coating can result in undesirable quality changes in filled chocolate confectionery products. The objective of this study was to monitor and model peanut oil migration in a 2-layer chocolate–peanut butter paste model confectionery. Spatial and temporal oil content changes were evaluated using magnetic resonance imaging. Five formulations of chocolate, which varied in chocolate particle size, milk fat content, and emulsifier level, were assessed at 2 temperatures, 20 and 30 °C. The spatial and temporal experimental data were modeled using a Fickian-based diffusion model, fitting for the diffusion coefficient, D , over a time frame of 17 d. Values of the diffusion coefficient ranged from 1.82 to 3.23 × 10⁻¹¹ m²/s for the chocolate formulations stored at 30 °C. No significant mass transfer took place in the 20 °C samples over the experimental time frame. This study describes the dynamic nature of the interface between the chocolate and peanut butter paste layers, quantifies the mass transfer from the peanut butter paste to the chocolate, and reinforces the importance of temperature control.     

Fate of Salmonella Tennessee in peanut butter at 4 and 22 degrees C

ABSTRACT:  This study was undertaken to determine survival characteristics of inocula of a 3-strain mixture of Salmonella Tennessee in 5 commercial brands of peanut butter (A, B, C, D, and E). Inoculated peanut butter was stored at 4 (refrigerator temperature) and 22 °C (room temperature) for up to 14 d. After 1, 3, 5, 7, and 14 d, surviving cells, including injured cells, were enumerated on appropriate selective agar, including use of the agar overlay method. Populations in samples inoculated with 10^6–7 CFU/g and stored for 14 d at 4 and 22 °C decreased by 0.15 to 0.65 and 0.34 to 1.29 log CFU/g, respectively, depending on the formulation. Peanut butter A showed a significantly lower number of S . Tennessee cells when stored at 22 °C for 14 d, compared to 4 °C ( P < 0.05). However, there was no significant difference between the levels of S. Tennessee at 4 and 22 °C in products B, C, D, and E ( P > 0.05).     

Crystallization of Cocoa Butter in Cocoa Powder

Cocoa powder quality is determined by its color, flavor, dispersion, and flow properties, which can be controlled via tempering. Design of a cocoa powder tempering profile, however, requires that the mechanism of cocoa butter crystallization in cocoa powder be fully understood. Low-fat (8–12%) and high-fat (20–24%) cocoas were sourced from two commercial manufacturers at varying degrees of alkalization and compared with two commercial cocoa butters. Unrefined paired cocoa powders and cocoa butters sampled from the hydraulic press were also evaluated. Isothermal crystallization kinetics and polymorphism of cocoa powders and cocoa butters were compared at 18, 21, and 24 °C using a direct time-domain nuclear magnetic resonance method, differential scanning calorimetry, and x-ray diffraction. Crystallization was also studied under dynamic tumbling conditions. It was found that cocoa butter in cocoa powder was nucleated by the cocoa powder matrix and transitioned to higher-stability polymorphs more rapidly than bulk cocoa butters. High-fat cocoas also exhibited enhanced crystallization kinetics relative to low-fat cocoas, showing that differences in the cocoa microstructure may influence crystallization behavior. Notably, alkalization did not significantly affect the crystallization behavior of most cocoa powders. Finally, it was found that tumbling conditions led to crystallization of βV and that caking, especially of high-fat cocoas, could be reduced by a static low-temperature hold step prior to tumbling. Overall, these results demonstrated that crystallization of cocoa butter in cocoa powder is influenced both by the intrinsic attributes of the cocoa powder as well as the conditions of the tempering process.     

Modifying the physical properties of butter using high-intensity ultrasound

The physical qualities of butter are affected by the physical properties of the cream used to make it. The objective of this study was to evaluate the effect of high-intensity ultrasound (HIU) on the physical properties of cream and butter. High-intensity ultrasound (frequency: 20 kHz, amplitude: 108 µm), often called sonication, was applied for 0, 10, 30, 60, and 90 s using a 1.27-cm-diameter tip to heavy cream (40% fat; 300 g) that was aged at 7.5°C with low agitation (40 rpm) for 90 min. Sonicated cream was churned at 7.5°C until butter grains were formed. The solid fat content (SFC), melting behavior, and average fat droplet size of cream were measured after HIU treatment. Butter was characterized by SFC and melting behavior immediately after production and was tested for SFC, melting behavior, and hardness after storage for 24 h at 5°C. High-intensity ultrasound did not affect the average fat droplet size of cream. Sonicating cream for 30, 60, and 90 s slightly decreased SFC due to the temperature increase (2–6°C) that occurred during HIU application. Two melting peaks were observed at approximately 17 and 33°C in all the cream samples. A significantly lower peak temperature was observed in cream sonicated for 10 s compared with creams sonicated for 30 and 60 s. A relatively shorter churning time of sonicated cream compared with nonsonicated cream was observed, possibly because HIU weakens the fat globule membrane. Two melting peaks were observed in all butter samples at approximately 16 and 33°C. Treatment with HIU for 10 to 60 s significantly increased the hardness of butter. When HIU was applied to cream for 10 s, the hardest butter was obtained, with the lowest onset temperatures and highest enthalpy values for both melting peaks. Treatment with HIU for 10 s promoted crystallization of low-melting-point triacylglycerols (TAG) during churning, which resulted in a harder material. Significantly lower enthalpy values for the high-melting-fraction TAG were observed in butters treated with HIU for 60 and 90 s compared with non-HIU-treated butter, which suggests that a longer duration of HIU promotes melting of high-melting-point TAG. The hardness of butter was correlated with the enthalpy values of the low-melting fraction and with total enthalpy values of fresh butter. However, further crystallization occurred in the butter during 24 h of storage at 5°C, and all differences in enthalpy values disappeared. In conclusion, exposure of cream to HIU can be used to modify the physical properties of butter, and the effects of HIU depend on the length of HIU treatment.     

Yak-milk-derived exosomes promote proliferation of intestinal epithelial cells in an hypoxic environment

Intestinal epithelial cells (IEC) are an important part of the intestinal barrier. Barrier function was disrupted under hypoxia, but milk-derived exosomes can regulate the intestinal barrier function. However, the mechanisms underlying the association between yak milk exosomes and hypoxia in IEC remain poorly understood. In this follow-up study, we proposed an effective optimization method for purifying yak-milk-derived exosomes. The Western blot analyses indicated that the expression of the proteins of the endosomal sorting complexes required for transport (TSG101), proteins of the tetraspanin family (CD63), and heat shock protein 70 (Hsp-70) proteins from yak-milk-derived exosomes were significantly higher than those in cow-milk-derived exosomes. Flow cytometry analysis showed that yak milk had 3.7 times the number of exosomes compared with cow milk. Moreover, we explored whether yak milk exosomes could facilitate intestinal cell survival under hypoxic conditions in vitro. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide results showed that yak-milk-derived exosomes significantly increased survival of IEC-6 cells with rates of up to 29% for cells incubated in hypoxic conditions for 12 h, compared with those of cow-milk-derived exosomes posttreatment (rates of up to 22% for cells incubated in hypoxic conditions for 12 h). Confocal microscopy revealed that the IEC-6 cells uptake more yak-milk-derived exosomes than cow milk in hypoxic conditions. Furthermore, the Western blot analyses indicated that yak-milk-derived exosomes significantly promote oxygen-sensitive prolyl hydroxylase (PHD)-1 expression and decrease the expression of hypoxia-inducible factor-α and its downstream target vascular endothelial growth factor (VEGF) in the IEC-6 cells. Further, yak-milk-derived exosomes significantly inhibited p53 levels. In conclusion, our findings demonstrate that yak-milk-derived exosomes more effectively activate the hypoxia-inducible factor signaling pathway, thus promoting IEC-6 cell survival, which may result in higher hypoxia tolerance than cow-milk-derived exosomes.     

固相分散萃取-离子对液相色谱法测定花生酱中苯甲酸和山梨酸

采用固相分散萃取技术处理样品,无水硫酸钠为分散剂,反相离子对色谱法测定花生酱中苯甲酸和山梨酸.色谱条件:C18柱,甲醇-5 mmol/L四丁基溴化铵水溶液(40:60,V/V)为流动相,检测波长230 nm.在0.5～100 μg/mL范围内线性良好,相关系数均为0.9997.两组分平均回收率91.7％和77.4％,相对标准偏差2.02％和2.99％,检出限分别为0.90 μg/g和1.35 μg/g.     

Rancimat法与Schaal烘箱法测定花生油和花生酱氧化稳定性的对比

分别采用Rancimat法与Schaal烘箱法测定花生油和花生酱的氧化稳定性,并对2种方法的相关性进行了分析。结果表明:用Rancimat法替代传统的过氧化值测定法评价花生油和花生酱的氧化稳定性是可行的。     

Maternal rumen and milk microbiota shape the establishment of early-life rumen microbiota in grazing yak calves

Early-life gut microbial colonization and development exert a profound impact on the health and metabolism of the host throughout the life span. The transmission of microbes from the mother to the offspring affects the succession and establishment of the early-life rumen microbiome in newborns, but the contributions of different maternal sites to the rumen microbial establishment remain unclear. In the present study, samples from different dam sites (namely, oral, rumen fluid, milk, and teat skin) and rumen fluid of yak calves were collected at 6 time points between d 7 and 180 postpartum to determine the contributions of the different maternal sites to the establishment of the bacterial and archaeal communities in the rumen during early life. Our analysis demonstrated that the dam's microbial communities clustered according to the sites, and the calves' rumen microbiota resembled that of the dam consistently regardless of fluctuations at d 7 and 14. The dam's rumen microbiota was the major source of the calves' rumen bacteria (7.9%) and archaea (49.7%) compared with the other sites, whereas the potential sources of the calf rumen microbiota from other sites varied according to the age. The contribution of dam's rumen bacteria increased with age from 0.36% at d 7 to 14.8% at d 180, whereas the contribution of the milk microbiota showed the opposite trend, with its contribution reduced from 2.7% at d 7 to 0.2% at d 180. Maternal oral archaea were the main sources of the calves' rumen archaea at d 14 (50.4%), but maternal rumen archaea became the main source gradually and reached 66.2% at d 180. These findings demonstrated the potential microbial transfer from the dam to the offspring that could influence the rumen microbiota colonization and establishment in yak calves raised under grazing regimens, providing the basis for future microbiota manipulation strategies during their early life.     

Identification and molecular mechanism of action of antibacterial peptides from Flavourzyme-hydrolyzed yak casein against Staphylococcus aureus

Antibacterial peptides can be released from yak milk casein. To date, the amino acid sequences and mechanism of action of yak casein–derived antibacterial peptides remain unknown. The current study identified antibacterial peptides from yak casein and their molecular mechanism of action. Our results showed that yak α-casein, β-casein, and κ-casein could be effectively hydrolyzed by Flavourzyme (Solarbio Science and Technology Co. Ltd.), and the 2-h hydrolysate showed the highest antibacterial rate of 43.07 ± 2.59% against Staphylococcus aureus. The 1,000 to 3,000 Da fraction accounted for 23.61% of the 2-h hydrolysate and had an antibacterial rate of 62.64 ± 4.40%. Three novel peptides with antibacterial activity were identified from this fraction, and the β-casein–derived peptide APKHKEMPFPKYP showed the strongest antibacterial effect (half-maximal inhibitory concentration = 0.397 mg/mL). Molecular docking predicted that APKHKEMPFPKYP interacted with 2 important enzymes of Staph. aureus, dihydrofolate reductase and DNA gyrase, through hydrophobic, hydrogen bonding, salt bridge, and π-π stacking interactions. Our findings suggest that the yak casein–derived peptides may serve as a potential source of natural preservatives to inhibit Staph. aureus.     

Composition,Structure, and Color of Fat Bloom Due to the Partial Liquefaction of Fat in Dark Chocolate

A type of fat bloom, which had not previously been fully characterized, was investigated to identify the state of its existence and its formation mechanism. Samples of bloom on solid chocolate resulting from the partial liquefaction of fat during temperature variations were analyzed to determine the crystal characteristics, fat contents, and triacylglycerol (TAG) compositions. Also, observation and elemental analyses were performed by scanning electron microscope with an energy-dispersive X-ray spectrometer, color analyses of minute regions were made by using PARISS^®, and Fourier-transform infrared (FT-IR) analyses were performed. The dark- and light-brown areas did not show any differences in fat content or TAG compositions that could lead to the observed color differences. Although differences in component distributions were noted in micrometer-sized regions, no relation to the colors was confirmed. The bloom samples in this study and bloom developed without a tempering process resembled each other in the tone of color at their discolored regions, but the states they adopted differed from one another. It is suggested that the color in this type of bloom was affected by the roughness and/or porosity of the microstructure and could also be a result of the coarsened fat crystal network and of the liquid fat migration.