Volume 17, Issue 3

The limited enzymatic hydrolysis gelation method was investigated using peanut protein isolate (PPI) without any coagulators. A peanut protein gel could be formed by enzyme treatment with Alcalase at low temperature (50–70 °C). The influence of enzymatic hydrolysis on the rheological and physicochemical properties was investigated. Structural changes in the PPI were characterized by analyzing the subunits, chemical forces, surface hydrophobicity, fluorescence spectra, and circular dichroism (CD) spectra. The results revealed that enzymatic hydrolysis significantly affected the conarachin II protein of PPI, and had little influence on conarachin I and the basic subunits of arachin. Hydrophobic interaction was the main chemical force active in the peanut protein gel. An increase in the surface hydrophobicity coupled with red-shifts of the fluorescence spectra indicated that inner hydrophobic regions were exposed after hydrolysis, resulting in gel formation via hydrophobic interactions. The CD spectra showed that significant changes occurred in the secondary structure of PPI, where the ordered PPI structure formed a more open structure after enzymatic hydrolysis.

This research explored the impact of in-vivo oral processing on the bolus properties of three rice varieties [white ponni (WP), mappillai samba (MS), and basmati (B)] that were selected based on variations in the amylose content. The amylose and dry matter content of the WP, MS, and B were 4.67, 7.48, and 13.8(%) and 69.57, 60.09, and 70.47(%), respectively. Mastication features (bite-size, chewing time, and chew cycles), bolus properties (particle size distribution, bolus moisture content, rheology, and starch hydrolysis), time-dependent bolus features (rate of incorporation of saliva and saliva content) and, temporal dominance of sensation (TDS) of cooked rice were studied. Results confirmed the significance of oral processing on various bolus characteristics. Moreover, a pronounced correlation between the morphology of rice varieties and mastication features was observed. The structure and textural characteristics of the different rice varieties (MS, WP, B) showed considerable effects on the consumption time (25.7 s, 22.2 s, 17.8 s) and chewing cycles (34, 31, 23). Rate of saliva incorporation was relatively lesser for MS as compared with WP and B. Solid loss followed the trends WP > MS > B. The total starch content of cooked rice boluseswas WP (82.69 ± 0.01%), MS (79.49 ± 0.01%), and B (71.74 ± 0.01%). Further, texture – TDS and flavor – TDS of all varieties were found to be strongly dependent on textural attributes, composition, and oro-sensory perception. This study provides a significant understanding of the oral processing behavior of rice and its bolus, considering the effect of variations in amylose content, texture, and morphology.

Ultraviolet treatment (UV-C) is well known for its antimicrobial effects and current research shows that it has the potential to inactivate microorganisms in milk at much lower temperatures than conventional thermal treatment. However, Ultraviolet irradiation may result in adverse effects on milk quality, which arises due to photo oxidation in the presence of oxygen. Limiting the dissolved oxygen content in milk can minimize oxidative damage and thus, result in a better product quality. Nitrogen purging could be an effective method for reducing dissolved oxygen from liquids. The present study evaluates effects of nitrogen purging (prior to UV treatment) on milk quality. It was found that nitrogen purged UV treated milk causes minimal changes to physicochemical properties of milk.

Osmotic dehydration (OD) is a drying process that consists in placing the food in contact with concentrated solutions of soluble solids to reduce its water activity. The use of moderate electric field (MEF) may promote increase of the mass transfer rates due to the non-thermal effects of electroporation and permeabilization of the cells. In this context, the objective of this study was to investigate the mass transfer process kinetics during apples OD assisted by MEF, evaluating the non-thermal effects of this emerging technology. The experiments were conducted with sucrose solutions (40, 50 and 60%, m/m) at 40 °C. Samples were submitted to electrical field strength (0, 5.5 and 11.0 Vcm −1 ), according to an experimental design. Results indicated that the application of MEF favoured water loss and solid gain. The effective mass diffusivities of water and solids increased as voltage applied increases. Moreover, MEF negatively influenced color and reducing capacity of the samples.

The drying procedure is a key to producing pasta of intended quality and with a specific price tag. However, the existing models are mainly to describe the drying process in a steady state. A mathematical model of tube-shaped pasta drying in a conveyor belt dryer with a stepwise heating supply allows determining the curve of temperature and moisture gradients for a tube-shaped pasta unit. It also helps select the best settings to minimize the heat-power costs while maintaining the good quality of a dried product. The given model describes the drying process in a true-to-life form and ensures the convergence of calculations to observations (deviation: 12.5%). The model was utilized to design a transient drying protocol for conveyor belt dryers with a stepwise heating supply. The proposed dryer has high service reliability and produces uniformly dried high-quality product.

Impacts of pulsed electric fields (PEF) on physicochemical properties, bioactive compounds, and furfural and hydroxymethylfurfural (HMF) formations were quantified for sour cherry juice (SCJ). pH, titratable acidity (TA), total soluble solids (TSS), a *, b *, chroma, and total monomeric anthocyanin content (TMAC) were not significantly affected by 0–0.0341 J/L. The initial total antioxidant capacity (TAC) significantly rose with all the PEF treatments but initial citric, malic, fumaric, oxalic, succinic (−)-epicatechin, ferrulic, gallic, luteolin, p -coumaric, and o -coumaric acids, Cy-3-sop, and Cy-3-glu did not significantly degrade with no formations of furfural and HMF. The best-fit regression models explained 60.1, 39.7, and 36.3% of variation in TAC, TMAC, and TSS, respectively. Frequency exerted a greater impact than did electric field strength (EFS) on TA, pH, TSS, total color difference (TCD), hue, chroma, TMAC, TAC, sinapic, oxalic, quinic and tartaric acids, Cy-3-glu-rut, and furfural formation. 350.9 µs, 6.78 kV/cm, and 98 Hz were pointed as optimal settings.

Yogurt production with starter culture at 41 °C in the presence of plant water extracts ( Momordica grosvenori , Psidium guajava , Lycium barbarum or Garcinia mangostana ) were studied to examine the effects on acidification, physicochemical properties, microbial growth, proteolytic activity, and exopolysaccharide (EPS) content. All plant-based yogurt reached a pH of 4.5 faster (300–330 min) than plain-yogurt (360 min). All plant water extracts stimulated Lactobacillus spp. (∼7.4 log 10  CFU/mL) and Streptococcus thermophilus (8.20–8.50 log 10  CFU/mL) growth except for G. mangostana which marginally inhibited Lactobacillus spp. growth (7.21 log 10  CFU/mL). M. grosvenori, L. barbarum, and G. mangonstana were significantly affected proteolysis of milk proteins (46.2 ± 0.8, 39.9 ± 0.5, & 35.8 ± 0.1 µg/mL; respectively) compared to plain-yogurt (26.3 ± 0.4 µg/mL). The presence of G. mangostana and L. barbarum resulted in an increase ( p  < 0.05) of total solids content (∼15.0%) and water holding capacity in yogurt (28.1 ± 1.2 & 26.5 ± 0.3%; respectively; p  < 0.05). In addition, M. grosvenori water extract enhanced ( p  < 0.05) syneresis of yogurt (1.78 ± 0.30%). L. barbarum yogurt showed the highest EPS concentration (220.9 ± 12.4 µg/L) among yogurt samples. In conclusion, the presence of plant water extracts positively altered yogurt fermentation, enhanced proteolysis of milk protein, and induced EPS production.

We aimed to develop an efficient process for producing red yeast rice (RYR) with different rice cultivars (Samkwang: used for cooking and Hangaru: used for processing) and amounts of added water (0–100%). Our analyses showed that Hangaru rice had a round starchy form with 18.62% amylose content, and Samkwang rice exhibited an angular starchy form with 15.29% amylose content. The in vitro enzymatic hydrolysis ratio was higher for Hangaru RYR (20.92–24.28%) than for Samakwang RYR (10.97–15.91%) with different amounts of water added. Hangaru RYR showed the highest color value with 60% added water; however, Samkwang RYR highest color value was at 40% added water. The total content of monacolin K was the highest (749.34 mg/kg) for Hangaru RYR treated with 60% added water. These results suggest that Hangaru rice supplemented with 60% water is the most suitable for producing RYR.