S. S. Arya

Degradation products of sorbic acid in aqueous solutions

Abstract Carbonyl compounds from autoxidising sorbic acid solutions were isolated as 2,4-dinitrophenyl hydrazones (DNPHs) and separated by TLC on silica gel G. Acetaldehyde and β-carboxylacrolein were found to be the major degradation products. Crotonaldehyde and acetone were also detected but in very small proportions. In the presence of amino acids, β-carboxylacrolein polymerises rapidly to brown pigments and its proportion decreases in the reaction mixture.

Differential scanning calorimetry and wide‐angle X‐ray scattering studies of bread staling

Wide angle X-ray scattering (WAXS) was used to follow the development of crystal size and strain during the staling of bread containing different additives. In this it was observed that one can classify the good anti-staling additives as gelatin, propylene glycol, maltodextrin and anti-staling enzyme corresponding to the order of increasing crystal size for a particular Bragg reflection in all the samples and correlate using DSC (differential scanning calorimetry) studies of all the bread compositions containing different additives.

Pro- or antioxygenic activity of tejpat (Cinnamomum tamala) and red chilli (Capsicum annum) in sunflower oil

The pro- or antioxygenic activity of tejpat and red chilli, their fractions extracted using various solvents, and of chlorophyll, capsaicin and dihydrocapsaicin were determined in refined sunflower oil at 37 °C. Tejpat and its fractions containing chlorophyll showed pro-oxygenic activity and the catalytic action increased with increase in concentration of chlorophyll in the fractions. On the other hand, fractions which did not contain chlorophyll, such as the aqueous extract, and chlorophyll-free spice or fractions freed of chlorophyll by column chromatography were devoid of pro-oxygenic activity. The ground red chilli and its 80:20 (v/v) ethanol/water fraction exhibited strong antioxygenic activity. On the other hand, the petroleum ether fraction showed marginal antioxygenic activity, whereas the water-soluble fraction was practically devoid of any activity in refined sunflower oil. The pungent constituents of red chilli, capsaicin and dihydrocapsaicin also exhibited considerable antioxygenic activity. © 1999 Society of Chemical Industry

Dynamic mechanical thermal analysis of chapati and phulka (Indian unleavened bread)

Abstract Glass transition temperature ( Tg ) and relaxation phenomena ( α ) of bread, chapati, phulka and phulka containing different anti-staling (A/S) additives such as glycerol, propylene glycol, maltodextrin, and anti-staling enzyme were determined using Dynamic Mechanical Thermal Analysis (DMTA). α -Transition which depends upon order of fall in modulus ( FE 1 ), span ( σ ) and peak amplitude ( A t ) of tan δ transition and Tg was drastically affected between bread and phulka, by incorporation of A/S agents in phulka and during its ageing (staling). During ageing Tg and A t increased, whereas FE 1 and σ decreased. Phulka containing glycerol, propylene glycol and A/S enzyme gave satisfactory results.

Suitability of antioxygenic salts for stabilization of fried snacks

Abstract Fried potato chips, banana chips and fried Bengalgram ( Cicer arietinum ) dhal were treated with antioxygenic salts containing butylated hydroxyanisole (BHA), butylated hydroxytoluene and tertiary butylated hydroquinone (TBHQ), and stored at 37 °C in polypropylene packs. Treatment with antioxygenic salts considerably retarded the rate of autoxidation of fats in the fried products, as indicated by changes in peroxide value, overall acceptability and concentration of total steam-volatile carbonyls. Maximum protection was provided by the antioxygenic salt containing TBHQ and minimum protection by the BHA-salt. During storage, the concentrations of all the carbonyls increased, but increases in the concentrations of pentanal, hexanal, heptanal, hexenal, heptenal, octenal and 2,4-decadienal were largest. Concentrations of antioxidants in antioxygenic salts also tended to decrease during storage.

Studies on glass transition temperature during staling of bread containing different monomeric and polymeric additives

Glass transition temperature (Tg) of bread containing different antistaling agents and also of bread superquenched and annealed in a DSC cell and outside, was determined using differential scanning calorimeter (DSC). Increase in Tg during the staling of bread correlated with firming as measured by Instron. Singlet Tg was an indication of miscibility or compatibility of bread components with each other. The lowest increase in Tg was found in bread containing propylene glycol (singlet) followed by glycerol (doublet), maltodextrin (broad), gelatin (singlet), antistaling enzyme (singlet), and polypropylene glycol (doublet) in the order of increase in Tg. Superquenching produced a maximum increase in Tg of bread.

Flavour degradation in dehydrated convenience foods: changes in carbonyls in quick-cooking rice and Bengalgram dhal

The carbonyl profiles of quick-cooking rice and Bengalgram (Cicer arietinum) dhal are reported. Freshly processed rice contained formaldehyde, acetaldehyde, acetone, butanal and hexanal, while freshly processed Bengalgram dhal contained 2,4-decadienals, propanal and 2-enals in addition to the above compounds. Incorporation of vanaspati (hydrogenated vegetable oil) and refined sunflower oil enhanced the proportion of acetone in quick-cooking rice and dhal. On storage, the proportion of hexanal, 2,4-decadienal and 2-heptenal, 2-octenal and 2-none-nal increased, while the proportion of acetone decreased considerably. The concentration of total carbonyls increased considerably on storage. Most of the additional aldehydes were formed from the oxidative degradation of lino-lenic and linoleic acids which decreased on storage. The rate of autoxidation, as measured by changes in peroxide value, was highest in untreated rice and dhals followed by samples containing refined sunflower oil, while the samples containing vanaspati autoxidized the slowest.