Physical and nutritional qualities of extruded weaning foods containing sorghum, pearl millet, or finger millet blended with mung beans and nonfat dried milk

Sorghum, pearl millet, and finger millet flours (60% of each) were blended with toasted mung bean flour (30%) and nonfat dry milk (10%) and extruded (Brabender single screw) to make precooked, ready-to-eat, weaning foods. The extruded foods had high cold paste viscosity, but their cooked paste viscosity was lower than that of the respective blends. Chemical scores of the extruded foods were 78 for sorghum, 80 for pearl millet, and 96 for finger millet. Protein digestibility corrected amino acid scores (PD-CAS) were similar for pearl millet (68%) and finger millet (69%); PD-CAS for sorghum was 57%. Total dietary fiber content of the foods ranged from 7.6 to 10.1%, with the soluble dietary fiber content of the foods being about 10% higher than that of the corresponding blends. Extrusion enhanced the in vitro protein digestibility of foods, but no marked difference occurred in the in vitro carbohydrate digestibility among the unprocessed blends and the extruded foods. The net protein ratio, protein efficiency ratio, and biological values were higher for the finger millet food than for the pearl millet food, probably because of the higher lysine content of the finger millet protein.     

Effects of Process Variables on the Denaturation of Whey Proteins during Spray Drying

The effects of varying feed concentration (20–40% w/v) and outlet temperature (60 to 120°C) on whey protein denaturation (determined by DSC) and solubility (at pH 4.6) have been investigated in a pilot-scale co-current spray dryer. The study confirms that low outlet gas temperatures (60 and 80°C) produce the lowest amount of denaturation and solubility loss, with almost complete denaturation observed at 120°C along with a less dramatic reduction in solubility. Slightly more denaturation and loss of solubility was found with a 40% feed concentration. It is hypothesized that crust formation, resulting in high particle temperatures while still maintaining a wet core, is likely to lead to high levels of denaturation.     

Microencapsulation of Docosahexaenoic Acid by Spray-Freeze-Drying Method and Comparison of its Stability with Spray-Drying and Freeze-Drying Methods

Producing docosahexaenoic acid (DHA) in powder form is a great challenge as oxidation of polyunsaturated DHA takes place during drying due to higher temperature operations. One solution to this problem is to microencapsulate the DHA, which may restrict the oxidation of polyunsaturated DHA. In this study, first time spray-freeze-drying (SFD) technique is used for microencapsulating DHA and compared the results with spray-drying (SD) and freeze-drying (FD) techniques. Emulsifier of Tween-40 yielded better stability in different emulsion stability studies. A study of Fourier transform infrared spectra confirmed the presence of DHA in all the microencapsulated samples. SFD method yielded microencapsulated DHA with lower peroxidation (protected from oxidation) than FD and SD methods due to low temperature operation. However, encapsulation efficiency (oil retention) of SFD microcapsules yielded slightly lower (71 %) than the SD (about 83 %) and FD (73 %) methods. The percentage of oxidation was lower (13 %) during SFD process, whereas higher in FD (31 %) and SD (33 %) processes. Storage study indicated that SFD microencapsulated powders showed lower peroxidation than FD and SD encapsulated powders. Moreover, morphology of spray-freeze-dried samples depicted spherical shape with fine pores on the surface, while spray dried process yielded spherical shape without pores, which in turn resulted in good rehydration behavior of the SFD powdered product.     

Physical,sensory, in-vitro starch digestibility and glycaemic index of granola bars prepared using sucrose alternatives

Granola bars were prepared using barley flakes, groundnut bits, cocoa powder, sucrose and/or sucrose alternatives (coconut sugar, fructooligosaccharide and inulin). Apart from sensory acceptance, nutritional composition, energy values and glycaemic responses (glycaemic index, GI and glycaemic load, GL) of the bars were evaluated. Physico-chemical properties and sensorial acceptance of granola bar made with coconut sugar and fructooligosaccharide were on par with those made with sucrose. Further, all formulated granola bars, except with inulin, were intermediate moisture foods. GI of all five formulations of granola bars was <55; ranging between 51 and 54.9, corresponding to low glycaemic food. Granola bars with coconut sugar had high GL (≥20), while bars prepared with FOS, inulin and without sugar were in the medium range (>10 to <20). Effect of choice of raw materials, complexity of matrix structure and particle size of ingredients on GI and GL of the bars is explained.     

Nanoliposomal encapsulation of chia oil for sustained delivery of α-linolenic acid

Chia oil is a popular source of ω-3 fatty acids, typically α-linolenic acid. This study reports the encapsulation of chia oil in nanoliposome to protect ω-3 fatty acids and to obtain a sustained release of chia oil during digestion. Nanoliposomal encapsulation was carried out using solvent evaporation, followed by sonication. The encapsulation process was conducted using different lipid contents, with different concentrations of soy phosphatidylcholine (S), Tween 80 (T) and volumes of the aqueous phase. The maximum encapsulation efficiency was found to be 88.31%, and the average particle size was 49.25 nm; a moderate repulsion among the particles was observed. Differential scanning calorimetry study revealed enhanced thermal stability of chia oil in nanoliposomes. A negligible release (3.39%) of encapsulated chia oil was observed in the simulated gastric fluid, and a 74.72% sustained release was recorded in the simulated intestinal fluid. This formulation can be a suitable supplement of ω-3 fatty acids for food and therapeutic applications.     

Impact of nonthermal food processing techniques on mycotoxins and their producing fungi

Mycotoxins are a significant threat to food safety and quality. Over the years, mycotoxins have been detected in almost all food and feed crops without any regional barrier. Conventional techniques for decontamination of mycotoxin involve physical, chemical, and biological methods, but these technologies often impact the quality of food in terms of changes in nutritional and sensory attributes. We examined the effects of nonthermal techniques on mycotoxins and their producing fungi to remove or reduce mycotoxin levels in food products without compromising food quality. Nonthermal technologies employ different lethal agents (including ozone, cold plasma, light, pressure, radiation, ultrasound, electric field, and magnetic field) to degrade mycotoxins while minimising product thermal exposure. However, the degradation pathway and toxicology of treated products need further research for a better understanding. With such food process development and optimisation efforts, food processors can employ various nonthermal technologies as tools for delivering consumer-desired mycotoxin-free food products with intact nutritional and sensory quality.     

An investigation of bread-baking process in a pilot-scale electrical heating oven using computational fluid dynamics

A computational fluid dynamics (CFD) model was developed for bread-baking process in a pilot-scale baking oven to find out the effect of hot air distribution and placement of bread on temperature and starch gelatinization index of bread. In this study, product (bread) simulation was carried out with different placements of bread. Simulation results were validated with experimental measurements of bread temperature. This study showed that nonuniform air flow pattern inside the oven cavity leads to uneven temperature distribution. The study with respect to placement of bread showed that baking of bread in upper trays required shorter baking time and gelatinization index compared to those in the bottom tray. The upper tray bread center reached 100 °C at 1200 s, whereas starch gelatinization completed within 900 s, which was the minimum baking index. Moreover, the heat penetration and starch gelatinization were higher along the sides of the bread as compared to the top and bottom portions of the bread.     

Impact of wheat bran addition on the temperature‐induced state transitions in dough during bread‐baking process

Wheat bran‐mediated effects on temperature‐induced state transitions of proofed bread dough were studied as function of its level of replacement (5%–15%) to wheat flour. Proofed dough was subjected to rheological tests at small deformations. During heating of proofed dough from 30 °C to 95 °C, the value of elastic modulus (G′) attained its maximum at a temperature () that represented peak gelatinisation temperature (T_P). Dough with 15% bran depicted significant increase in T_P over other formulations. Bran addition increased glass transition temperature (T_g) of dough and suppressed drop in elastic modulus (G′) at T > T_g. The above events resulted in decreased loaf‐specific volume and increased crumb hardness. The former was caused by retarded bubble expansion during initial stages of baking, explained by reduced uniaxial and biaxial extensibilities of dough. Mean bubble size depicted an inverse relationship with the hardness of breadcrumb.