Thermal processing and Maillard reaction (MR) affect the nutritional and sensorial qualities of milk. In this paper an olive mill wastewater phenolic powder (OMW) was tested as a functional ingredient for inhibiting MR development in ultrahigh-temperature (UHT)-treated milk. OMW was added to milk at 0.1 and 0.05% w/v before UHT treatment, and the concentration of MR products was monitored to verify the effect of OMW phenols in controlling the MR. Results revealed that OMW is able to trap the reactive carbonyl species such as hydroxycarbonyls and dicarbonyls, which in turn led to the increase of Maillard-derived off-flavor development. The effect of OMW on the formation of Amadori products and N-ε-(carboxymethyl)-lysine (CML) showed that oxidative cleavage, C2-C6 cyclization, and the consequent reactive carbonyl species formation were also inhibited by OMW. Data indicated that OMW is a functional ingredient able to control the MR and to improve the nutritional and sensorial attributes of milk.

The application of phenolic compounds to suppress Maillard chemistry and off-flavor development in ultrahigh-termperature (UHT)-processed milk during processing and storage was investigated. Five phenolic compounds were examined for structure-reactivity relationships (catechin, genistein, daidzein, 1,2,3-trihydroxybenzene, and 1,3,5-trihydroxybenzene). The levels of key transient Maillard reaction (MR) intermediates (reactive carbonyl species) and select off-flavor markers (methional, 2-acetyl-2-thiazoline, 2-acetyl-1-pyrroline) were quantified by LC-MS/MS and GC-MS/ToF, respectively. The addition of phenolic compounds prior to UHT processing significantly reduced the concentration of MR intermediates and related off-flavor compounds compared to a control sample (p < 0.05). All phenolic compounds demonstrated unique structure reactivity and, notably, those with a more activated A-ring for aromatic electrophilic substitution (catechin, genistein, and 1,3,5-trihydroxybenzene) showed the strongest suppression effect on the off-flavor markers and reactive carbonyl species. Sensory studies were in agreement with the analytical data. The cooked flavor intensity was rated lower for the recombination model samples of the catechin-treated UHT milk compared to the control UHT milk. Additionally, consumer acceptability studies showed catechin-treated UHT milk to have significantly higher liking scores when compared the control sample (Fisher's LSD = 0.728).

The compounds responsible for the bitter taste of aged "sharp" Cheddar cheese were characterized. Sensory-guided fractionation techniques using gel permeation chromatography and multi-dimension semi-preparative reversed-phase high-performance liquid chromatography revealed the presence of multiple bitter compounds. The compounds with the highest perceived bitterness intensity were identified by tandem mass spectrometry de novo peptide sequencing as GPVRGPFPIIV, YQEPVLGPVRGPFPI, MPFPKYPVEP, MAPKHKEMPFPKYPVEPF, and APHGKEMPFPKYPVEPF; all originated from β-casein. Subsequent quantitative liquid chromatography-tandem mass spectrometry analysis reported that the concentrations of GPVRGPFPIIV, YQEPVLGPVRGPFPI, and MPFPKYPVEP increased during maturation by 28.7-, 3.1-, and 1.8-fold, respectively. When directly compared to young "mild" Cheddar, APHGKEMPFPKYPVEPF was reported only in the sharp Cheddar cheese, whereas the concentration of MAPKHKEMPFPKYPVEPF did not change. Further taste re-engineering sensory experiments confirmed the importance of the identified peptides to the bitterness of sharp Cheddar. The bitter intensity of the aged "sharp" Cheddar model (mild Cheddar with equivalent concentrations of the five bitter peptides in the sharp sample) was rated as not significantly different from the authentic sharp Cheddar cheese. Among the five peptides, GPVRGPFPIIV was reported to be the main contributor to the bitterness intensity of sharp Cheddar. Furthermore, a difference from control sensory test also confirmed the significance of the bitter taste to the overall perception of aged Cheddar flavor. The sharp Cheddar model was reported to be significantly more similar to aged "sharp" Cheddar in comparison to the young "mild" Cheddar cheese sample.

Response surface methodology (RSM) was utilized to investigate the dose-response relationships of a phenolic mixture (catechin, genistein and daidzein) as a pre-thermal processing technique to reduce reactive carbonyl species (RCSs; glyoxal, methylglyoxal and 3-deoxyglucosone) in ultra-high temperature (UHT) bovine milk. A modified derivatization technique for RCSs was developed to overcome quantitative error caused by interference from the phenolic compounds. For the statistical analysis, a Box-Behnken 3-factor (catechin, genistein and daidzein) 3-level (0.17, 0.645 and 1.12 mM) design was employed. In general, all phenolic mixtures were able to reduce RCSs in UHT milk; some compositions reported RCSs levels at or below levels reported in pasteurized milk. Predictive models with no significant lack of fit (p > 0.05), high R(2)-values (0.886-0.979) and good predictive power were developed. ANOVA analysis of the glyoxal levels indicated that only linear effects of each phenolic compound had a significant effect (p < 0.05) meaning that no significant interactions between the different phenolic compounds influenced glyoxal levels. Linear, cross product and quadratic effects of factors were reported (p < 0.05) for methylglyoxal, indicating more complicated interactions between the phenolic compounds. Both linear and quadratic effects were also reported (p < 0.05) for 3-deoxyglucosone. Overall, based on canonical analysis, catechin seemed to be the most influential factor for the reduction of RCSs in UHT milk. In summary, RSM provided a basis to understand phenolic structure-reactivity and to optimize the composition of a tertiary mixture of phenolic compounds for reduction of RCSs in UHT milk.

Patients who are malnourished or at-risk for malnutrition often benefit from the consumption of oral nutritional supplements (ONS). ONS supply a range of micro- and macro-nutrients, and they can be used to supplement a diet or provide total nutrition. Since ONS are specially formulated products, all ONS ingredients—including carbohydrates—are added ingredients. This may seem to be at odds with the growing public health discourse on the need to reduce “added sugars” in the diet. However, carbohydrate is an essential nutrient for human health and is a critical ingredient in ONS. Helping to educate patients on the value of “added sugars” in ONS may be useful to improve compliance with nutritional recommendations when ONS are indicated. This perspective paper reviews the important roles of “added sugars” in ONS, in terms of flavor, function, and product formulation.