Sunita Adak

A green approach for starch modification: Esterification by lipase and novel imidazolium surfactant.

Starch being one of the most abundant polysaccharides in nature has been subjected to modification to enhance its applicability. Modification by esterification involves acylation of hydroxyl groups of glucose units to form starch esters. Lipases, as catalysts have emerged as a promising alternative to chemical processes. Although ionic liquids and microwave assisted heating are emerging as green technology yet their use along with lipases for starch modification has not been probed. In the present study esterification of corn starch employing Rhizopus oryzae lipase, microwave irradiation and novel imidazolium surfactants has been attempted. At 80% irradiation, 1:3 starch/oleic acid molar ratio, 150 IU enzyme, and 50μmol of [C16-3-C16im]Br2 maximum degree of substitution (DS=2.75) was attained. The modified starch showed better hydrophobicity and thermoplasticity with corresponding structural changes depicted by FTIR, XRD and SEM. These properties advocate the usefulness of the modified starch in food and biopolymer sectors.

Role of spacer length in interaction between novel gemini imidazolium surfactants and Rhizopus oryzae lipase.

An insight into the effects of new ionic liquid-type gemini imidazolium cationic surfactants on the structure and function of the lipases is of prime importance for their potential application. Changes in the activity, stability and structure of Rhizopus oryzae lipase in the presence of novel gemini surfactants, [C16-3-C16im]Br2 and [C16-12-C16im]Br2 were probed in the present study. Surfactant with shorter spacer length, [C16-3-C16im]Br2 was found to be better in improving the hydrolytic activity and thermal stability of the lipase. For both the surfactants, activation was concentration dependent. CD spectroscopy results showed a decrease in α-helix and an increase in β-sheet content in the presence of these surfactants. A higher structural change observed in presence of [C16-12-C16im]Br2 correlated with lower enzyme activity. Isothermal titration calorimetric studies showed the binding to be spontaneous in nature based on sequential two site binding model. The forces involved in binding were found to differ for the two surfactants proving that the spacer length is an important factor which governs the interaction. These surfactants could be used as promising components both in enzyme modification and media engineering for attaining the desired goals in biocatalytic reactions.

Food Biotechnology: A Step Towards Improving Nutritional Quality of Food for Asian Countries

BACKGROUND Food-based technologies established itself as a vast, inter-disciplinary and multifaceted research area are at crossroads of scientific and technological advancements. The review of patents reveals that growing concerns over the source of nourishment for the burgeoning population, its quality, quantity and safety, along with associated human and environmental welfare has inspired global researchers to implement several new bio-based technologies. OBJECTIVE Biotechnological interventions in food sector have been aimed at enhancing/modifying taste, aroma, shelf-life, texture and nutritional value of food products employing fermentation, enzyme technology, nanotechnology and molecular biology. The use of whole microbes as a source of nutrition and genetically modified microorganisms to be used as food or genetically modified food have been successfully attempted, which has addressed the mass population and malnutrition. Further, the processing techniques have been improved along with the proper utilization of food wastes for the generation of many useful byproducts. CONCLUSION The article covers broadly the impact of biotechnological interventions in food sector. Techniques mostly discussed include not only the nutrient enriched food production but also byproduct utilization through proper improvisation of food waste into bioenergy, biomanure and other value added products, which is of great economic and environmental importance. This article reviews the overall aspects in relation to some of the recent advancements in food sector.

Mycosynthesized Nanoparticles: Role in Food Processing Industries

Green synthesis of nanoparticles (NPs) is an evolving branch of nanotechnology. The use of fungi for the synthesis of NPs is referred to as mycosynthesis of metal NPs. Fungal endophytes have been recognized as important sources of a variety of structurally novel active secondary metabolites with anticancer, antimicrobial, and other biological activities. This mode of synthesis of metal nanoparticles is gaining more importance owing to its simplicity, rapid rate of synthesis of NP of attractive and diverse morphologies, and elimination of elaborate maintenance of cell cultures and eco-friendliness. Presently, the researchers are looking into the development of cost-effective procedures for producing reproducible, stable, and biocompatible metal NPs using fungal cultures. The present chapter is an exhaustive overview that assesses the role of fungi in the synthesis of nanoparticles, the mechanism involved in the synthesis, the effect of different factors on the reduction of metal ions in developing low-cost techniques for the synthesis, and recovery of nanoparticles. Finally, the application of nanoparticles in food processing industries, i.e., antimicrobial mechanisms, etc., has also been discussed.

In vitro efficacy of Bryophyllum pinnatum leaf extracts as potent therapeutics.

ABSTRACT Leaf extracts of Bryophyllum pinnatum (BPEs) are used in several countries. Contextually, evaluation of the therapeutic potential of these was carried out in this study to explore antioxidant and antityrosinase potential through different in vitro methods. The radical scavenging properties of BPEs were studied using various techniques, based on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) dot blot thin-layer chromatography (TLC) method, electron paramagnetic resonance (EPR) spectroscopy, metal chelation, β-carotene bleaching, inhibition of DNA breakage on agarose gel, and lipid peroxidation inhibition using liver and brain microsomes. EC50 values of the results reflected that aqueous-methanolic BPE was the most active one. Antibrowning potential of the fresh leaf extract showed an antityrosinase property, with EC50 values of enzymatic assay of tyrosinase inhibitory activity further advocating the findings.