Nihir Shah

Evidence for xylooligosaccharide utilization in Weissella strains isolated from Indian fermented foods and vegetables

Six strains isolated from fermented food were identified as Weissella species by 16S rDNA sequencing, clustering with the species pair W. confusa/W. cibaria. The strains were analysed for growth on glucose, xylose and xylooligosaccharides (XOS). All strains were xylose positive using the API CHL 50 test. Growth on XOS was observed for strains 85, 92, 145 and AV1, firstly by optical density measurements in microtitre plates and secondly in batch cultures also confirming concomitant decrease in pH. Analysis of XOS before and after growth established consumption in the DP2-DP5 range in the four XOS-fermenting strains. XOS were consumed simultaneously with glucose, while xylose was consumed after glucose depletion. Cell-associated β-xylosidase activity was detected in the XOS-fermenting strains. Analysis of genomic data suggests this activity to be linked with genes encoding glycoside hydrolases from family 3, 8 or 43. No endo-β-xylanase activity was detectable. Major end products were lactate and acetate. A higher ratio of acetic acid to lactic acid was obtained during growth on XOS compared with growth on glucose. This is the first report on utilization of XOS in Weissella, indicating an increased probiotic potential for XOS-utilizing strains from the species pair W. confusa/W. cibaria, but also showing that XOS utilization is strain dependent for these species.

Antimicrobial Profile of Lactic Acid Bacteria Isolated from Vegetables and Indigenous Fermented Foods of India against Clinical Pathogens Using Microdilution Method.

In dairy and food industries lactic acid bacteria(LAB)have been used in form of starter culture that plays vital role in fermentation;as flavouring and texturizing or as preservative agents.There is increasing evidence that lactobacilli which inhabit the gastrointestinal tract develop antimicrobial activities and participatein the host’s defence system[1].During fermentation,most of the LAB produces a number of different compounds like organic acids,hydrogen peroxide,diacetyl,acetaldehyde,carbon dioxide,polysaccharides,and proteinaceous compounds called bacteriocins or bacteriocinogenic peptides[2-3].Such metabolites exert antimicrobial activity and are

Partially hydrolyzed guar gum as a potential prebiotic source

Guar galactomannan was enzymatically hydrolyzed to obtain partially hydrolyzed guar gum which can be utilized as prebiotic source. In present study, growth of probiotics (Lactic Acid Bacteria strains) were studied with glucose, partially hydrolyzed guar gum and native guar gum. All the six strains were galactose &/or mannose positive using the API CHl 50 test. Almost all these strains showed an ability to assimilate partially hydrolyzed guar gum with respect to increase in optical density and viable cell count with concomitant decrease in the pH of the growth medium. Streptococcus thermophilus MD2 exhibited higher growth (7.78 log cfu/ml) while P. parvulus AI1 showed comparatively less growth (7.24 log cfu/ml) as compared to used lactobacillus and Weissella strains. Outcomes of the current study suggest that partially hydrolyzed guar can be considered as potential prebiotic compound that may further stimulate the growth of potentially probiotic bacteria or native gut microflora.

Recent advances in biosynthesis of vitamin and enzyme from food grade bacteria

Fermented food provides plenty of vital nutrients and bioactive components that affect a number of functions of human body in a positive way. Fermented dairy and food products can be made more functional by incorporating probiotic bacteria such as strains belonging to genera Lactobacillus and Bifidobacterium. A few strains of such food grade bacteria are capable of synthesizing essential biomolecules such as vitamins, enzymes, exopolysaccharides, bacteriocins or bioactive peptides during the fermentation that aid into the functional and technological properties of the products. Present paper summarises the recent advances found in the field of biosynthesis of vitamins and enzymes. The outcomes of several studies are indicative of promising applications at commercial level.

Application of Nanotechnology in the Food Industry: Present Status and Future Prospects

Abstract Nanotechnology deals with the design and development of organic and inorganic materials at the nanoscale, with tailor-made physical, chemical, and biological properties. Research in nanoscience has revealed potential applications in medical diagnostics and therapeutics for human beings and livestock animals. It has proved its value in molecular computing, energy production, and structural materials. Conversely, food nanotechnology is an emerging field, successfully employed in direct or packaged food products for food quality, food safety, food fortification, sensory improvement, shelf life extension, and food packaging. This novel technology can be applied in the food sector through nanosensors, tracking devices, targeted delivery of essential components, new product development, precision processing, smart packaging, and so on. Nanoscience primarily benefits the development of functional foods, nutraceuticals, standard milk, and other food products. However, several evidences revealed that nanoparticles can enter the food chain and may cause the buildup of toxic contaminants in the food system, which can have a negative influence on human health. This chapter will summarize the present status and future prospects of nanotechnology and its potential applications and limitations in the food industry.

Therapeutic Potential of Flaxseed

Abstract Flaxseed, also known as linseed, is one of the most prominent emerging functional foods. It has been reported that consumption of flaxseed helps in reducing the risks of cardiovascular diseases, rheumatoid arthritis, autoimmune, and neurological disorders. Several clinical and epidemiological studies have indicated that flaxseed oil, the richest plant source of omega-3 fatty acid, is also associated in reduction of dyslipidemia and chronic kidney diseases due to its antiinflammatory properties. A number of studies have shown that flaxseed proteins possess potential angiotensin I-converting enzyme (ACE) inhibitor activities, antioxidative, and antihypertensive properties. Similarly, several researchers have proven that flax fibers and lignans (secoisolariciresinol diglucoside, SDG) are positively associated for the treatment and prevention of obesity, bowel syndrome, and hormone-sensitive cancerous diseases. Ayurveda and traditional Chinese medicine share many common approaches and have a long history in the practice of using flaxseeds as a remedy of cough, skin, and gastro-intestinal disorders. Various nutraceutical preparations of flax and flaxseed oil, such as Essentiale, Lipostabil, Efamol, and Essaven are available in global market for the treatment of general fatigue, pain, atherosclerosis, eczemas, and different diseases. The purpose of this chapter is to delineate the recent findings of flaxseed on the physiological functionality of nutraceutical formulations, along with their applications in foods.

Microbial Production of Low-Calorie Sugars

Consumption of high-calorie sweetener has been associated with major health risks, particularly weight gain, increased risk of diabetes, hypertension, and cardiovascular problems. Worldwide obesity has almost doubled since 1980. In 2014, more than 1.9 billion people were overweight, and of these more than 600 million were obese. Low-calorie sweeteners may provide a way to avoid these health issues. They can be categorized into 2 groups: intense sweeteners, such as neotame, acesulfame-K, aspartame, saccharin, sucralose, etc., and naturally-occurring, reduced-calorie, bulk sweeteners, such as erythritol, mannitol, xylitol, sorbitol, isomalt, lactitol, trehalose, hydrogenated starch hydrolysates, hydrogenated glucose syrups, etc. In addition to the food industry, these sugars are also widely used in the pharmaceutical, medical, and chemical industries. Chemical processes for the production of these rare sugars have many disadvantages, such as the utilization of pure substrate, challenging purification steps, and the utilization of high temperature and pressure; thus leading to very high costs. Alternative processes based on the use of microbes (i.e., yeast, fungi, and bacteria, especially lactic acid bacteria) have been suggested. Utilization of this rare, sugar-producing, food-grade bacteria might lead to “natural” low-calorie foods. With the advent of metabolic engineering it has also been possible to generate novel compounds and produce existing compounds at higher levels.

Shelf-life Study of Pouch Packed UHT Milk- A Qualitative Approach

The analysis of raw milk subjected to UHT process revealed no seasonal variations in any of the physico-chemical parameter except significant increase in microbial spore count. During storage of UHT pouch milk, significant changes were observed after 45 days for overall acceptability score, pH, protein content, lactose content at 37±1 oC whereas no microbial spores were found during entire shelf-life study. Based on results, it seems that the Maillard browning could be responsible for bringing pronounced changes in physico-chemical parameters as well as decreasing the degree of overall acceptability of UHT milk. The initially cooked/burnt flavour noticed by panellist was overruled by other off-flavours like chalky, stale, etc. after 45 days. However, the UHT milk was acceptable till the end of storage period.