Multiple-factor mathematical modeling of glycine-glucose browning

Physicochemical and Microbiological Quality Assessment of Artisanal and Commercial Recipes of Cucurbita ficifolia Jams with High Sensory Acceptability

Artisanal cayote jam consumption is widespread in Latin-American countries. This jam is prepared from the pulp of Cucurbita ficifolia Bouché. Here, an artisanal cayote jam recipe and a reduced-calorie artisanal cayote jam recipe were defined through sensory analysis. The defined jams showed higher overall acceptance and flavour quality compared to commercial ones. The low-calorie jam showed overall acceptance similar to the artisanal product, with no differences in the flavour quality. The cayote jams were characterised by determining physicochemical parameters and microbial flora. Artisanal jams presented physicochemical properties similar to commercial products. The variability of °Brix was greater (40-67); pH were 4.7-5.4, aw were 0.832-0.940. Reduced-calorie jam had pH ≥ 5, °Brix of 30-46 and aw>0.920. The colour of the jams showed significant variability depending on the recipe: L* (26.1-48.1), a*(1.6-4.6), b*(2.1-14.9). Cayote jams were found to be rich in carbohydrates (31-70%) and energy value (134-290 kcal/100 g), with lower contents of fibre, sodium, fat, and protein. The microbiological analysis indicate that there are no risks related to the consumption of cayote jams, although there are indications of potential quality deterioration during subsequent storage due to the development of yeasts and when no preservatives are used in the jam recipes. The characteristic microflora of cayote jams was composed by Penicillium sp., Aspergillus sp., Cephalosporium acremonium, Candida sp. and Rhodotorula sp. These results will benefit artisanal cayote jam producers in Latin-American countries and other regions where C. ficifolia is cultivated, by highlighting the autochthonous value of cayote and contributing to a nutritionally diverse diet.

Nonenzymatic Browning of Amorphous Maltose/Whey Protein Isolates Matrix: Effects of Water Sorption and Molecular Mobility

Nonenzymatic browning (NEB) reactions often affect the nutritional quality and safety properties of amorphous food solids. Developing a proper approach to control the NEB reaction has been of particular interest in the food industry. An NEB reaction in an amorphous maltose/Whey protein isolates (WPI) matrix containing L-lysine and D-xylose as reactants were studied at ambient temperatures aw ≤ 0.44 and 45~65 °C. The results indicated that the presence of NEB reactants barely disturbed the water sorption behavior of the matrix. The Guggenheim–Anderson–de Boer (GAB) constants and Qst values of the studied samples were affected by storage conditions as the migration of sorbed water among monolayers occurred. The rate of color changes and 5-hydoxymethylfurfural (5-HMF) accumulation on the matrix were accelerated at high ambient temperatures aw, reflecting the extent of NEB reaction increases. Since the strength concept (S) could give a measure of molecular mobility, the extent of the NEB reaction was governed by the molecular mobility of the matrix as the activation energy (Ea) of 5-HMF production minimized at solids with high S values. We found that the S concept had a considerable potential usage in controlling the NEB reaction on amorphous sugar–protein solids. This data set has practical significance in the comprehensive understanding of manipulating the diffusion-limited chemical reactions on low-moisture food solids.

Evolution of nonenzymatic browning during the simulated Msalais-production process in models of grape juice

Msalais is a wine fermented from boiled grape juice. Nonenzymatic browning (NEB) greatly affects the quality of Msalais, but to date its mechanism has not been systematically analyzed. In the current study, the evolution of NEB during Msalais production was investigated using models of grape juice. 5-Hydroxymethylfurfural (5-HMF), browning index (BI), yellowness index (YI), sample absorbance at 420 (A420), and b* increased during heating, with a clear transition point at 110 min. The Maillard reaction (MR) was the major contributor to NEB. Vitamin C (VC) facilitated NEB in the late stage of heating. During heating that lasted over 130 min, glucose contributed to NEB more than fructose, while the reverse was true for heating lasting less than 130 min. Proline (Pro) was the most important amino acid in facilitating NEB. BI and A420 decreased during fermentation, while increasing slightly during wine storage. In conclusion, this study identified the evolution of NEB during the Msalais process, which will facilitate the control of traditional Msalais production for improved wine quality.