Effect of storage materials and duration on the physicochemical, pasting and microstructural properties of low glycemic index rice flour.

This study investigated physicochemical, glycemic index, pasting and microstructural properties of low glycemic index rice flour (LGIRF) stored in two different packaging materials (low density polyethylene-LDPE and metalized polyester-Met-PE) under accelerated storage conditions (38 ± 2 °C and 90-92% RH) for three months. The different properties were evaluated after every one month. Protein, fat, fibre and carbohydrate content decreased slightly while, water activity, moisture and ash of both control and LGIRF increased significantly with storage (P < 0.05). Total starch, in vitro glycemic index and glycemic load were higher in control and decreased during storage (P < 0.05). However, resistant starch, total sugars, reducing sugars and degree of sweetness in LGIRF exhibited higher, although non-significant variation relative to control during storage. Pasting properties revealed that peak and breakdown viscosities decreased while final and setback viscosities increased during storage (P < 0.05) however holding viscosity and pasting temperature exhibited non-significant variation (P > 0.05). Further, all pasting properties were significantly higher in control except pasting temperature (P < 0.05). All farinographic properties exhibited non-significant difference during storage and were significantly higher in control. Overall, while comparing LDPE and MeT-PE samples non-significant variation was observed in all properties. Microstructural studies showed that integrity of starch granules in LGIRF samples were least altered during storage.

Functional characterization of biopolymer based composite film: Incorporation of natural essential oils and antimicrobial agents.

Rosemary (REO), mint essential oil (MEO), nisin and lactic acid were incorporated at 0.5% to develop a novel functional packaging film including chitosan pectin and starch polymers (0.75:1.5:0.75 w/w). Inclusion of REO and nisin significantly (p ≤ 0.05) improved water barrier properties (0.014 g.mm/m224h), tensile strength (25.95 MPa) and thermal stability as compared to control. ATR-FTIR spectra and XRD pattern elucidated structural interaction between EO's and biocomposite films. Addition of REO of and nisin increased microsctructural heterogeneity and opacity (2.78). Incorporation of REO and nisin exhibited the highest inhibitory activity against all tested pathogenic strains (Bacillus subtilis, Escherichia coli, and Listeria monocytogenes). The antioxidant properties of biocomposite films were analyzed using reducing power, metal chelation, DPPH and ABTS radical scavenging assays, which enhanced significantly (p ≤ 0.05) with the addition of MEO and REO. This study validated that incorporation of natural additives in active biocomposite films offers promising functional ingredients for packaging materials for various food applications.

Emerging concepts in the nutraceutical and functional properties of pectin-A Review.

Pectin is a structural heteropolysaccharide found ubiquitously in terrestrial plants. It finds diverse food applications such as that of a gelling agent, stabilizer, and fat replacer. In the pharmaceutical arena, pectin exhibits a number of functions, from decreasing blood fat to combating various types of cancers. This review shows the shift of pectin from its conventional roles to its progressive applications. Insights into the advances in the production of pectin, the role it plays as a nutraceutical, possible prebiotic potential and a delivery vehicle for probiotics, and food applications are highlighted. Bioactive and functional properties of pectin are discussed and how the structural built up defines them, is emphasized. As a biopolymer, the applications of pectin in active packaging are also mentioned.

Enzymatic hydrolysis of whey and casein protein- effect on functional, rheological, textural and sensory properties of breads.

Milk proteins were hydrolyzed by papain and their effect on the rheological, textural and sensory properties of bread were investigated. Water absorption capacity, emulsification capacity, foam volume, foam stability and solubility of Whey and casein protein concentrates and their hydrolysates were determined. The farinograph parameters of wheat flour and blends of wheat flour with casein and whey protein and their hydrolysates were determined to evaluate changes in water absorption capacity, dough development time, dough stability time and mixing tolerance index. The incorporation of WPC, casein and their hydrolysates up to the level of 5 % showed dough properties comparable to control. It was also found that 5 % level incorporation of milk proteins and their hydrolysates have no drastic effect on physical and sensory attributes of bread. The pasting properties showed significant decrease (p ≤ 0.05) when compared with wheat flour at all levels of addition of whey and casein protein concentrates and hydrolysates. Scanning electron microscopy of bread samples shows disruption in the well-defined protein - starch complex of wheat flour bread and the structure of gluten was weak as the concentration of whey protein increases in the wheat flour bread.