Effect of γ-Irradiation on Colour, Functional and Physicochemical Properties of Pearl Millet [Pennisetum glaucum (L) R. Br.] Cultivars

The influence of non-thermal technologies on color pigments of food materials: An updated review

The color of any food is influenced by several factors, such as food attributes (presence of pigments, maturity, and variety), processing methods, packaging, and storage conditions. Thus, measuring the color profile of food can be used to control the quality of food and examine the changes in chemical composition. With the advent of non-thermal processing techniques and their growing significance in the industry, there is a demand to understand the effects of these technologies on various quality attributes, including color. This paper reviews the effects of novel, non-thermal processing technologies on the color attributes of processed food and the implications on consumer acceptability. The recent developments in this context and a discussion on color systems and various color measurement techniques are also included. The novel non-thermal techniques, including high-pressure processing, pulsed electric field, ultrasonication, and irradiation which employ low processing temperatures for a short period, have been found effective. Since food products are processed at ambient temperature by subjecting them to non-thermal treatment for a very short time, there is no possibility of damage to heat-sensitive nutrient components in the food, any deterioration in the texture of the food, and any toxic compounds in the food due to heat. These techniques not only yield higher nutritional quality but are also observed to maintain better color attributes. However, suppose foods are exposed to prolonged exposure or processed at a higher intensity. In that case, these non-thermal technologies can cause undesirable changes in food, such as oxidation of lipids and loss of color and flavor. Developing equipment for batch food processing using non-thermal technology, understanding the appropriate mechanisms, developing processing standards using non-thermal processes, and clarifying consumer myths and misconceptions about these technologies will help promote non-thermal technologies in the food industry.

Characterization of silver carp myosin glycated with phosphorylated konjac oligo-glucomannan

BACKGROUND

Myosin (Ms) is abundant in fish meat, but it has limited application in the food industry because of its low solubility and thermal stability. Our previous reports found that these functional properties of Ms can be significantly improved after glycation with konjac oligo-glucomannan (KOG). However, the effects of phosphorylated KOG (PKOG) on physicochemical, structural and functional properties of silver carp Ms are still unknown.

RESULTS

This study characterized the silver carp Ms protein glycated with PKOG at 50 °C and 75% relative humidity for 48 h. As degree of phosphorylation increased, free amino content increased, whereas degree of grafting decreased. Meanwhile, isoelectric point (pI) reduced, however, PKOGs showed no differences in pI. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis suggested the formation of glycoconjugates, and scanning electron microscopy revealed thinner flakes and uneven appearance of glycoconjugates. Fourier transform infrared spectroscopy indicated that the amide I, II and III bands of Ms were changed by the glycation. Ms became highly soluble in 0.5 mol L^-1 NaCl with increased phosphate addition in PKOGs. Thermal stability of Ms was effectively improved when heated at 80 °C for 60 min.

CONCLUSION

Glycation with appropriate PKOG might be a promising method for Ms modification because of the resulting improvement in solubility and thermal stability. © 2021 Society of Chemical Industry.

Effect of heat treatment and γ-irradiation on pasting, rheological, and fungal load of whole and dehulled millets

Millets are important food crops in food systems and application of physical treatments could improve the functional properties of millet-based products. Therefore, we investigated the effect of heat and γ-irradiation treatments on the pasting, rheological, and microbial load of whole and dehulled millets (sorghum, foxtail millet, and pearl millet). Moreover, similarity in treatment effect was evaluated by principal component analysis (PCA). The results revealed the significant (p < 0.05) decrease in pasting properties of whole and dehulled millets, except for pasting temperature (71.03 to 74.88 °C). Likewise, significantly (p < 0.05) decreased tendency was observed for all rheological properties, except for phase angle (0.05 to 0.30°) and yield point (13 to 5089). Samples showed a significant (p < 0.05) reduction in fungal growth (89.75 × 10⁴ to 4.46 × 10⁴ CFU/g) compared to control (110.30 × 10⁴ CFU/g). Moreover, samples individually formed 3 clusters (clusters 1: sorghum, 2: pearl millet, and 3: foxtail millet) based on pasting properties, which was confirmed by PCA. Therefore, the findings concluded that the effect of heat and γ-irradiation would be necessary to decrease pasting, rheological, and no microbial growth characteristics of dehulled and whole millets for the development of specific millet-based food products.