Narpinder Singh

Morphological, thermal and rheological properties of starches from different botanical sources

Corn, rice, wheat and potato are the main sources of starches which differ significantly in composition, morphology, thermal, rheological and retrogradation properties. Cereal starches contain a significant quantity of phospholipids, while potato starch is rich in esterified phosphorus. Potato starch exhibits higher swelling power, solubility, paste clarity and viscosity than wheat, rice or corn starches. Morphological characteristics, such as shape and size of the starch granules, exhibit significant differences. Potato starch granules are smooth–surfaced, oval and irregular or cuboidal-shaped while corn, rice and wheat starch granules are angular, pentagonal and angular; and spherical and lenticular–shaped, respectively. Corn, rice and wheat starch granules are less smooth–surfaced than potato starch granules. Potato starch granules are largest (<110 μm) in size followed by wheat (<30 μm), corn (<25 μm) and rice (<20μm) starches. Gelatinization temperatures (To, Tp, Tc) and enthalpies of gelatinization (ΔHgel) of starches from different sources also differ significantly. Corn and rice starches generally show higher transition temperatures than wheat and potato starches while the ΔHgel values are higher for potato and wheat starches. Potato starch shows a higher tendency towards retrogradation than the cereal starches. The rheological properties, such as storage modulus (G′) and loss modulus (G″) of the starches from the different sources increase to a maximum and then drop during heating of all the starches. Potato starch shows highest peak G′, G″ and lower tan δ than corn, rice and wheat starches during the heating cycle.

Studies on the morphological, thermal and rheological properties of starch separated from some Indian potato cultivars

The starches separated from five different Indian potato cultivars (Kufri Chandermukhi, Kufri Badshah, Kufri Jyoti, Kufri Sindhuri and S1) were investigated for morphological, thermal, rheological, turbidity and water-binding properties. The starch separated from all the five potato cultivars had a granule size ranging between 15–20 μm and 20–45 μm. The shape of starch granules varied from oval to irregular or cuboidal. Starch isolated from cv. Kufri Badshah had largest irregular or cubiodal granules while starch from cv. Kufri Chandermukhi had small and oval granules. The transition temperatures and enthalpy of gelatinization (ΔHgel) were determined using differential scanning calorimetry (DSC). The enthalpy of retrogradation (ΔHret) of gelatinized starch was also determined after 14 days of storage at 4°C using DSC. Kufri Chandermukhi starch showed the lowest ΔHgel and ΔHret while Kufri Badshah starch showed the highest values. ΔHgel and ΔHret values of 12.55 J/g and 6.42J/g, respectively, for Kufri Chandermukhi starch against 13.85 J/g and 8.61 J/g, respectively, for Kufri Bhadshah starch were observed. Rheological properties of starches from different potato cultivars, measured using the Dynamic Rheometer during heating and cooling, also differed significantly. The starch from cv. Kufri Badshah showed the highest peak G′ and G″ and lowest tan δ. The starches having higher peak G′(G′ at gelatinization temperature) showed higher breakdown in G′ and vice versa. The turbidity of gelatinized aqueous starch suspensions from all potato cultivars increased with increase in storage period. Starches with low water binding capacity had higher G′ and G″ and lower tan δ values.

Quality evaluation of different types of Indian honey

Chemical composition, flow behaviour indices and overall acceptability of the most popular types of honey produced in India were investigated. Trifolium honey showed the highest specific gravity, diastatic number, total acidity, free fatty acids content, consistency coefficient and overall acceptability. However, Eucalyptus lanceolatus honey showed the highest value for lactone and conductivity. Linear regression models for the formation of HMF as a function of time at different temperatures showed that Trifolium honey had fastest rate of HMF formation followed by Eucalyptus lanceolatus and Brassica juncea honey.

Amylose-lipid complex formation during cooking of rice flour

The effects of cooking rice flour in the presence of myristic, palmitic and stearic acid on amylose-lipid complex formation, water solubility and pasting properties were studied. Different fatty acids were added to rice flour, at 1.5, 3.0 and 4.5% levels, and cooked in Visco-amylograph at 95°C for 30, 60 and 90 min. Amylose-lipid complex formation increased and water-solubility decreased with the increase in levels of all the fatty acids in rice paste cooked for 30–90 min. Complexing of amylose with all the fatty acids increased with the increase in cooking time. Myristic acid had the highest ability to form the complex and stearic acid the lowest. Iodine spectra of rice paste cooked with and without lipids were also determined to confirm the formation of amylose-lipid complexes. Both λmax and ratios of absorbances at 630 and 520 nm decreased with the increase in levels of all the fatty acids. Myristic acid caused a greater reduction in λmax and ratios of absorbance. Addition of all the fatty acids increased the pasting temperature, peak viscosity, viscosity at 95°C and viscosity at 50°C of rice paste. Consistency coefficient and flow behaviour indices of rice pastes cooked in the presence of different fatty acids were also determined using a Brookfield viscometer. Consistency coefficient increased with the increase in levels of all the fatty acids and the increase was more pronounced with myristic acid.

Relationship of Granule Size Distribution and Amylopectin Structure with Pasting, Thermal, and Retrogradation Properties in Wheat Starch

Starches separated from 18 Indian wheat varieties were evaluated to see relationship of granule size distribution and amylopectin structure with pasting, thermal, and retrogradation properties. Average diameter of A-, B-, and C-granules among different starches varied between 23.0 and 28.5, 10.0 and 12.0, and 2.3 and 2.7 mum, respectively. Amylopectin chain length distribution varied significantly, short length chains (DP 6-12) and long length chains (DP > 24) ranged between 44.5 and 52.4% and 3.7 and 6.5%, respectively, whereas amylose content ranged between 18.2 and 28.8%. Short length chains of amylopectin had inverse relationship with starch gelatinization temperatures T(o), T(p), and T(c). Starches with higher crystallinity had higher enthalpy of gelatinization and lower swelling power. Paste characteristics were mainly dependent upon granule type and all pasting parameters except pasting temperature, showed significant positive correlations with A-granules and negative with the proportion of B- and C-granule.

Effect of liquid whole egg, fat and textured soy protein on the textural and cooking properties of raw and baked patties from goat meat

Abstract Effects of addition of liquid whole egg (LWE), fat and textured soy protein (TSP) on textural and cooking properties of goat meat patties were studied. Textural properties of raw and baked patties were measured using an Instron Universal Testing Machine. Regression models were computed for textural and cooking properties as well as overall acceptability scores of patties as a function of LWE, fat and TSP. TSP showed greatest effect on cohesiveness, puncture force, back extrusion force and hardness of both raw and baked patties. While fat showed the highest effect on gumminess, chewiness and adhesiveness of raw patties, LWE improved the juiciness of the patties, lowered the shrinkage and cooking losses. Addition of TSP significantly decreased overall acceptability of baked patties, particularly at highest addition level (20%). The majority of the models had an R2 over 0.9, indicating they are appropriate and can be used to describe the effect of LWE, fat and TSP on textural and cooking properties of goat meat patties.

Physico-chemical, morphological, thermal, cooking and textural properties of chalky and translucent rice kernels

Studies were undertaken to compare physico-chemical, morphological, thermal, cooking and textural properties of chalky and translucent kernels separated from three rice cultivars. Physico-chemical properties, such as 1000 kernel weight, bulk density, kernel hardness, length-breath (L/B) ratio and amylose content, were determined. The morphological properties of chalky and translucent kernels were studied using scanning electron microscopy while the thermal properties were determined by differential scanning calorimetery. The chalky kernels separated from different cultivars showed higher 1000 kernel weight and bulk density but lower kernel hardness and amylose content than their counterpart translucent kernels. Microscopic analysis revealed that the cells, as well as amyloplast, were loosely packed in the chalky kernels. Chalky grains showed higher transition temperatures, enthalpy of gelatinization, peak height index and gelatinization range than the translucent grains. The cooking and textural properties of chalky and translucent kernels differed significantly. The chalky kernels from different varieties showed lower values for cooking (cooking time, water uptake, L/B ratio and elongation ratio) and textural parameters (packability, cohesiveness, chewiness, hardness) than the translucent kernels.

Prognostic value of serum cardiac troponin I in ambulatory patients with chronic renal failure undergoing long-term hemodialysis: A two-year outcome analysis

OBJECTIVES We sought to evaluate the prognostic value of cardiac troponin I (cTnI) in asymptomatic, ambulatory patients with chronic renal failure treated with long-term hemodialysis. BACKGROUND Smaller, short-term follow-up studies on this subject have given conflicting results. METHODS A total of 126 ambulatory patients with chronic renal failure treated with long-term hemodialysis were followed for two years for all-cause mortality, cardiac mortality, all-cause hospital admissions and cardiac hospital admissions. Serum cTnI was measured before dialysis at the time of study entry. RESULTS One hundred two patients had normal serum levels of cTnI (< or =0.03 ng/ml) and 24 patients had elevated levels (0.015 +/- 0.007 vs. 0.053 +/- 0.029 ng/ml, p < 0.0001). No significant difference in all-cause mortality (20 vs. 4 deaths), cardiac mortality (4 vs. 1 death), all-cause hospital admissions (1.74 +/- 1.72 vs. 1.25 +/- 1.19 admissions/patient) or cardiac admissions (0.52 +/- 0.89 vs. 0.33 +/- 0.76 admissions/patient) was present between the patients with normal cTnI levels and those with elevated cTnI levels. Serum cTnI was not significantly different between patients who died versus those who survived (0.022 +/- 0.019 vs. 0.022 +/- 0.021 ng/ml). Serum cTnI was not an independent predictor of all-cause mortality, cardiac mortality, all-cause admissions or cardiac admissions. Age (older) and serum albumin (lower) were independent predictors of all-cause mortality, whereas a history of myocardial infarction was an independent predictor of cardiac mortality. Serum sodium (lower) was an independent predictor of all-cause hospital admissions, whereas hypertension and previous myocardial infarction were independent predictors of cardiac admissions. The best predictors of the time to death were age (older) and serum sodium level (lower), irrespective of the serum cTnI levels. CONCLUSIONS Cardiac troponin I has a limited role in predicting mortality and hospital admissions in asymptomatic patients with chronic renal failure treated with long-term hemodialysis.

Physicochemical, rheological and cookie making properties of corn and potato flours

Abstract The physicochemical and rheological properties of corn flour and flours made from three potato cultivars (Kufri Jyoti, Kufri Badshah and Pukhraj) were studied. Potato flour showed higher amylose content, water absorption index and solubility than corn flour. The rheological properties (G′, G″, η′ and tan δ), measured using a dynamic rheometer, of corn and potato flours differed significantly. Potato flours showed higher G′, G″ and η′ than corn flour. The potato flours made from different cultivars also showed significant differences in various rheological parameters. Kufri Jyoti flour showed the highest G′, G″ and η′ among the potato flours. The effects of blending corn flour and potato flours at different levels (2, 4 & 6%) with wheat flour on cookie-making properties were also studied. The addition of both corn and potato flours improved the cookie spread factor and lowered cookie fracture force. However, the effect of potato flours on cookie spread and fracture force were higher than corn flour. Colour parameters (L∗, a∗, b∗) of cookies were measured using a Hunter colorimeter. L∗ value of cookies decreased while a∗ and b∗ values increased with increase in level of both corn flour and potato flours. The addition of potato flours brought greater changes in L∗, a∗ and b∗ values than corn flour at corresponding levels.

A comparison between Helianthus annuus and Eucalyptus lanceolatus honey

A comparison between physico-chemical, enzymatic activities and rheological properties of Helianthus annuus and Eucalyptus lanceolatus honey was made. Eucalyptus lanceolatus honey showed higher protein, diastase and catalase activity than Helianthus annuus honey, while proline, conductivity, total acidity, free acids and lactone content were higher in Helianthus annuus honey. Consistency coefficient and activation energy for flow were lower for Helianthus annuus than Eucalyptus lanceolatus honey. Confirmation of monofloral origin of honey types was accomplished through microscopic examination. The effects of convective and microwave heating on hydroxymethylfurfural (HMF) formation in both honey types were also investigated. Total acidity, free acids and lactone content increased in both honey types during heating. HMF formation varied linearly with temperature and time of heating in both honey types. Microwave heating of both honey types also caused an increase in HMF formation. Effect of storage of honey, heated under different conditions, on HMF content was also investigated. Statistical analysis revealed that storage duration had the greatest effect on HMF formation, followed by heating duration and heating temperature, in Helianthus annuus honey, while heating duration showed the most pronounced effect, followed by heating temperature and duration, in Eucalyptus lanceolatus honey.