Kawaljit Singh Sandhu

Studies on physicochemical and pasting properties of Taro (Colocasia esculenta L.) flour in comparison with a cereal, tuber and legume flour

The physicochemical and pasting properties of taro (Colocasia esculenta L.) flour were investigated and compared with flours from other botanical sources. Proximate composition, color parameters, water and oil absorption, foaming characteristics and pasting properties (measured using Rapid visco analyzer) of flours were related to each other using Pearson correlation and principal component analysis (PCA). Taro flour was significantly (P < 0.05) different from other flours in exhibiting highest carbohydrate, water absorption, and lower protein, foaming capacity and setback viscosity. Peak viscosity of taro flour was lower in comparison to potato flour but higher than that of soya and corn flours. Several significant correlations between functional and pasting properties were revealed both by PCA and Pearson correlation. PCA showed that taro and potato flours were located at the left of the score plot with a negative score, while soybean and corn flours had a large positive score in the first principal component.

Functional, thermal and pasting characteristics of flours from different lentil (Lens culinaris) cultivars

Flours from four lentil cultivars (‘LL-912’, ‘LL-699’, ‘LL-56’, and ‘LL-147’) were characterized for their functional, thermal and pasting properties. Results showed that water and oil absorption capacity of flours were 1.5–1.7 and 0.92–1.13 g/g, respectively. The minimum concentration of flours needed for gelation was 12 to 14% while the foaming capacity was 33.9–47.3%. The transition temperatures (To, Tp and Tc) and enthalpies (ΔHgel) associated with gelatinization varied significantly among different lentil cultivars. Several significant correlations were observed among different flour properties as revealed by Pearson correlation and principal component analysis (PCA). PCA showed that ‘LL 56’ and ‘LL 147’ cultivars differed greatest degree in the properties of their flours. The pasting properties of flours showed considerable variation when studied by rapid visco analyzer.

Pasting properties of Tamarind (Tamarindus indica) kernel powder in the presence of Xanthan, Carboxymethylcellulose and Locust bean gum in comparison to Rice and Potato flour

Effects of addition of different levels of gums (xanthan, carboxymethylcellulose and locust bean gum) on the pasting properties of tamarind kernel, potato and rice flour were studied by using Rapid Visco-Analyzer (RVA). Tamarind kernel powder (TKP) varied significantly (P < 0.05) from rice and potato flours with respect to its highest protein, ash and fat contents. The results of RVA analysis indicated that pasting properties of flour/gum mixtures were dependent upon the concentration and type of the gums. Peak, breakdown and final viscosity increased with increase in gum concentration in the flour/gum mixture, but the effect was more pronounced for rice and potato flour than for TKP which showed much lower viscosity responses to all of the gums. Among the three gums studied, the increase in viscosity was significantly higher with addition of locust bean gum followed by xanthan while the lowest was observed with carboxymethylcellulose.

A Comparison of mango kernel starch with a novel starch from litchi (Litchi chinensis) kernel: Physicochemical, morphological, pasting, and rheological properties

ABSTRACT A novel starch was isolated from litchi kernel and compared with mango kernel starch. The properties studies were physicochemical, morphological, pasting, rheological, X-ray diffraction, and morphological. Litchi kernel starch had significantly (p < 0.05) higher amylose content and solubility, whereas its swelling power and paste clarity were lower than mango kernel starch. Peak viscosity and breakdown viscosity of litchi kernel starch were lower than mango kernel starch; however, it showed higher setback viscosity. The scanning electron microscopy revealed the presence of starch granules varying in size and shape from small to large and oval to elliptical, respectively, in litchi kernel starch. The mean length of small and large litchi starch granules was 9.52 and 50 µm, respectively, while the mean breadth of small and large litchi starch granules was 7.14 and 35.7 µm, respectively. X-ray diffractions of both litchi and mango kernel starches showed typical A-type patterns. During heating, litchi kernel starch showed higher peak G’ (storage modulus), G’’ (loss modulus), and breakdown in G’ in comparison to mango kernel starch. The peak tan δ of litchi and mango kernel starch was <1, which indicated that both litchi and mango kernel starches were more elastic than viscous.

Starch Nanoparticles: Their Preparation and Applications

The word “nano” originates from the Greek term “dwarf.” Nanoparticles are generally recognized as those with a particle size below 100 nm which enables novel applications and benefits. Materials and devices with nanostructures have different properties from the materials they are made. Starch is a widely available, abundant biopolymer produced in plants by the process of photosynthesis and stored in the form of granules. The starch granules are in microsize which can be broken down into nanosize using different nanotechnological methods. These nano-sized particles are safe for human health and are increasingly utilized in food and nonfood industries. Nanotechnology, in general, is making the most significant progresses in biomedical application, including novel drug delivery practices in which starch nanoparticles can be used as drug carriers. Other potential applications of starch nanoparticles include their use in waste water treatment where they can replace the costly activated carbon as adsorbents. It has also attracted interest as a packaging material due to its better barrier properties. Their addition in natural rubber matrix improved barrier and mechanical properties and thus they are used commercially in tire making. Recently starch nanoparticles are found to have applications as fat replacers and emulsion stabilizers. Due to growing interest in starch nanoparticles, in the last decade, various methods have been developed for their synthesis. Acid hydrolysis, regeneration, and physical methods are widely used for the preparation of starch nanoparticles.

Fermented pearl millet (Pennisetum glaucum) with in vitro DNA damage protection activity, bioactive compounds and antioxidant potential

In the present study, pearl millet cultivar PUSA-415 was fermented by solid state fermentation (SSF) process using Aspergillus sojae (MTCC-8779) as starter culture. The fermentation was carried out for the period of ten days. The effect of SSF on phenolic content, condensed tannin content, antioxidant potential and DNA damage protection of pearl millet during different fermentation period was determined. Results showed that SSF and thermal processing significantly affect the bioactive profile and antioxidant potential of bio-transformed pearl millet. Extracts prepared from 6th days fermented pearl millet flour exhibited the highest TPC, antioxidant potential and DNA damage protection activity. Qualitative and quantitative analysis of bioactive compounds were done by HPLC. During SSF, production of enzymes (α-amylase, β-glucosidase and xylanase) as well as specific bioactive compounds (ascorbic acid, gallic acid and p-Coumaric acid) was significantly increased. Thus, bio-transformed Aspergillus sojae fermented pearl millet could be used in preparation of functional foods and novel nutraceuticals in health promotions. Chapatti was formulated from unfermented as well as fermented flour and the effect of thermal processing on bioactive compounds and antioxidant potential was studied. Thermal processing resulted in decrease in TPC of both, AFM and UFM by 4.75-16.27% and increase in CTC by 38.52-67.41%.

Fermentation of Cereals: A Tool to Enhance Bioactive Compounds

Popularity of antioxidant-rich food products are increasing day by day. Cereals being a major source of nutrients are still deficient in some basic nutritional components. So to improve their nutritional value, functional and sensory properties, interest has been shown to develop bioprocesses for the production of bioactive compounds and their applications in the field of food, chemical and pharmaceutical industries. Solid-state fermentation (SSF) has received greater attention as fermentation has the potential to release phenolic compounds from plant-based matrices. The potential application of fermentation process to convert the profile of phenolic compounds is mainly due to the release of bound phenolic compounds as a consequence of the degradation of the cell wall structure by microbial enzymes into unique metabolites through different bioconversion pathways.

Recent Advances in Biodegradable Films, Coatings and Their Applications

Biodegradable films have appeared as an alternative for synthetic plastics. These films have generated huge attention in recent years as they are beneficial over synthetic films. These films increase the shelf life of foods because they limit migration of moisture and gases. Biomaterials such as polysaccharides, proteins and lipids are generally chosen for the formation of biodegradable films. Functional properties of biodegradable films and coatings can be improved by adding compounds with antimicrobial and antioxidant properties. Biodegradable materials can be used in variety of food products such as dairy products, ready-to-eat meals, meat products, beverages, frozen products, dehydrated products and fruits and vegetables. Different protein-based biodegradable films from different plant sources such as soy, zein, wheat protein, peanut protein, cotton seed, pumpkin, sesame, pea, mung bean, castor bean, faba bean, kidney bean, casein, whey protein have been discussed in detail. Films prepared from cellulose, starch, pectin, and seaweeds have also been discussed.

Effect of heat processing on the antioxidant properties of pearl millet ( Pennisetum glaucum L.) cultivars

The effect of toasting (mild heat treatment) and cooking (severe heat treatment) on color and antioxidant properties of flours from pearl millet cultivars grown in India were investigated. The antioxidant properties studied were total phenolic content (TPC), total flavonoids content (TFC), antioxidant activity (AOA), metal chelating activity (MCA), and ABTS+ scavenging activity. Toasting resulted in increase in antioxidant properties (TPC, TFC, AOA, MCA, and ABTS+) as well as hunter a* and b* values. The hunter L* value was, however, decreased. Except for increase in hunter L* value and MCA all other antioxidant properties of flours studied showed a decrease after cooking as compared to flours from their native counterparts. Comparison of both the processing methods revealed that except for MCA, all other antioxidant properties of flours after toasting had significantly (p < 0.05) higher values than after cooking.

Starch: Its Functional, In Vitro Digestibility, Modification, and Applications

Starch is a naturally occurring biopolymer widely available in nature. Amylose and amylopectin are two macromolecular components of starch granules. Starch can be characterized by using a variety of techniques including differential scanning calorimeter (DSC), rapid visco analyzer (RVA), rheometer, and X-ray diffraction. Native starches have limitations such as low shear resistance, thermal decomposition, and high tendency of retrogradation which limits their use in industrial food applications. These shortcomings can be easily overcome by starch modifications by a variety of physical, chemical, and enzymatic modifications. In recent years, glycemic index (GI) has become a potentially useful tool in planning diets for patients suffering from diabetes, dyslipidemia, cardiovascular disease, and even certain cancers. On the basis of digestibility, starches can be classified into readily digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). The starches from different botanical vary in their RDS, SDS, and RS contents. SDS and RS contents of starches have a variety of health benefits and these can be increased by different methods. Apart from variety of food applications, starch also has huge usage in nonfood area.