Many of the sauces used in frozen meals are oil-in-water emulsions that consist of fat droplets dispersed within an aqueous medium. This type of emulsion must remain physically and chemically stable throughout processing, freezing, storage, and defrosting conditions. Knowledge of the fundamental physicochemical mechanisms responsible for the stability of emulsion-based sauces is needed to design and fabricate high-quality sauces with the desired sensory attributes. This review provides an overview of the current understanding of the influence of freezing and thawing on the stability of oil-in-water emulsions. In particular, it focuses on the influence of product composition (such as emulsifiers, biopolymers, salts, and cryoprotectants), homogenization conditions, and freezing/thawing conditions on the stability of emulsions. The information contained in this review may be useful for optimizing the design of emulsion-based sauces for utilization in commercial food products.

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Cow milk is a common allergenic food, and cow milk-derived cheese retains an appreciable level of allergenicity. The specific and sensitive detection of milk protein residues in foods is needed to protect milk-allergic consumers from exposure to undeclared milk protein residues contained in foods made with milk or milk-derived ingredients or made on shared equipment or in shared facilities with milk or milk-derived ingredients. However, during cheese ripening, milk proteins are degraded by chymosin and milk-derived and bacterial proteases. Commercial allergen-detection methods are not validated for the detection of residues in fermented or hydrolyzed products. The objective of this research was to evaluate commercially available milk ELISA kits for their capability to detect milk protein residues in aged Cheddar cheese. Cheddar cheese was manufactured at a local dairy plant and was aged at 5°C for 24 mo, with samples removed at various time points throughout aging. Milk protein residues and protein profiles were measured using 4 commercial milk ELISA kits and sodium dodecyl sulfate-PAGE. The ELISA data revealed a 90% loss of milk protein residue signal between the youngest and oldest Cheddar cheese samples (0.5 and 24 mo, respectively). Sodium dodecyl sulfate-PAGE analysis showed protein degradation throughout aging, with the highest level of proteolysis observed at 24 mo. Results suggest that current commercial milk ELISA methods can detect milk protein residues in young Cheddar cheese, but the detection signal dramatically decreases during aging. The 4 evaluated ELISA kits were not capable of detecting trace levels of milk protein residues in aged cheese. Reliable detection of allergen residues in fermented food products is critical for upholding allergen-control programs, maintaining product safety, and protecting allergic consumers. Furthermore, this research suggests a novel use of ELISA kits to monitor protein degradation as an indication of cheese ripening.

Objectives Infant feeding influences early development of the gut microbiome, colonization pattern, and community structure. Metabolites, including short- and branched-chain fatty acids (S/BCFA) (e.g., butyrate, propionate), produced by colonic bacteria serve as signaling molecules, influence immunity, and reduce luminal pH in the gastrointestinal environment. The objective of this study was to evaluate stool S/BCFA and pH in infants fed with different sources of dietary protein. Methods In this multicenter, double-blind, controlled, parallel-group, pilot study, healthy term infants were randomized to receive one of two infant formulas (IF): amino-acid based (AAF; n = 25) or extensively hydrolyzed cow's milk protein (EHF; n = 28) from Baseline (1-7 days of age) up to 60 days of age. A human milk reference group (HM; n = 25) received mother's own milk over the same period. Diethyl ether extractions of S/BCFA from stool samples (Baseline, Day 30, and Day 60) were quantified by gas chromatography (Clarus 580; PerkinElmer) using a fused silica capillary column (Nukol 30m × 0.25mm id × 0.25μm film). Mean stool S/BCFA (μmol/g) and pH were analyzed by repeated measures analysis of variance (ANOVA). Results Complete stool data (all study time points) were available for 49 participants. Stool pH (∼6) was similar among groups at Baseline with no significant changes for HM and EHF groups through Day 60. The AAF group was significantly higher at Days 30 and 60 (Figure 1). Total SCFA were similar for all groups through Day 60. Butyrate increased significantly from Baseline to Day 60 in the EHF group (P = 0.026) and was significantly higher vs HM at Days 30 and 60 (P = 0.0009 and 0.0004 respectively). Butyrate was significantly higher for AAF vs HM at Day 60 only (P = 0.038). Propionate was significantly higher for EHF and AAF at Day 30 (P = 0.0009 and < 0.0001 respectively) and AAF only at Day 60 (P = 0.005) vs HM. Total and individual BCFA increased for AAF and EHF groups vs HM through Day 60. Conclusions Distinct patterns of pH and microbial metabolites were demonstrated for infants receiving mother's own milk compared to amino acid-based or extensively hydrolyzed protein formula. Providing different sources of dietary protein early in life may influence gut microbiota and metabolites. Funding Sources Mead Johnson Pediatric Nutrition Institute. Supporting Tables, Images and/or Graphs

Objectives Infant feeding practices play a central role in development of gut microbiome and community structure. Our goal was to test the hypothesis that diets with intact or extensively hydrolyzed proteins or free amino acids may differentially affect the intestinal microbiota composition and immune reactivity. Methods This multicenter, double-blind, controlled, parallel-group, pilot study compared stool microbiota outcomes from Baseline (1-7 days of age) up to 60 days of age in healthy term infants. Infants received mother's own milk (assigned to human milk [HM] reference group) (n = 25) or were randomized to receive one of two infant formulas: amino-acid based (AAF; n = 25) or extensively hydrolyzed cow's milk protein (EHF; n = 28). Neither study formula included added Lactobacillus rhamnosus GG. DNA was extracted (Baseline, Day 30, Day 60), 16S rRNA genes were amplified and sequenced (Illumina MiSeq), and exact amplicon sequence variants (ASV) were assigned using the DADA2 model. Alpha (Shannon, Simpson, Chao1) and beta diversity (Bray Curtis distance) and differential abundance in taxa were analyzed. Relative ASV enrichment (Baseline vs Day 60) was visualized using heat maps and taxa abundance was analyzed by DESEq2 in R (ver 3.4.3). Results Complete stool data (all study time points) were available for 49 participants. Baseline alpha diversity measures were similar among groups. The HM group remained stable throughout the study. However, alpha diversity measures by Day 60 were significantly higher for AAF and EHF groups compared to HM. Significant group differences in beta diversity at Day 60 were detected (P < 0.001); AAF and EHF clustered more closely compared to the HM group. Relative Bifidobacterium abundance increased over time and was significantly enriched at Day 60 in the HM group (Figure, A). At Day 60, a significant increase in members of Firmicutes was detected for AAF and EHF groups; a decrease in Enterobacteriaceae (Escherichia) was observed for EHF (Figure, B). Conclusions Distinct patterns of early neonatal microbiome establishment were demonstrated for infants receiving mother's own milk compared to amino acid-based or extensively hydrolyzed protein infant formulas. Providing different sources of dietary protein early in life may impact gut microbiome development. Funding Sources Mead Johnson Pediatric Nutrition Institute. Supporting Tables, Images and/or Graphs