Non-destructive determination of grass pea and pea flour adulteration in chickpea flour using near-infrared reflectance spectroscopy and chemometrics.

BACKGROUND: In order to obtain more economic gains, some food products are adulterated with low-cost substances, if they are toxic, they may pose public health risks. This has called forth the development of quick and non-destructive methods for detection of adulterants in food. Near-infrared reflectance spectroscopy (NIRS) has become a promising tool to detect adulteration in various commodities. We have developed rapid NIRS based analytical methods for quantification of two cheap adulterants (grass pea and pea flour) in a popular Indian food material, chickpea flour. RESULTS: The NIRS spectra of pure chickpea, pure grass pea, pure pea flour and adulterated samples of chickpea flour with grass pea and pea flour (1-90%) (w/w) were acquired and preprocessed. Calibration models were built based on modified partial least squares regression (MPLSR), partial least squares (PLS), principal component regression (PCR) methods. Based on lowest values of standard error of calibration (SEC) and standard error of cross-validation (SECV), MPLSR-NIRS models were selected. These models exhibited coefficient of determination (R2 ) of 0.999, 0.999, SEC of 0.905, 0.827 and SECV of 1.473, 1.491 for grass pea and pea, respectively. External validation revealed R2 and standard error of prediction (SEP) of 0.999 and 1.184, 0.997 and 1.893 for grass pea and pea flour, respectively. CONCLUSION: The statistics confirmed that our MPLSR-NIRS based methods are quite robust and applicable to detect grass pea and pea flour adulterants in chickpea flour samples and have potential for use in detecting food fraud. © 2022 Society of Chemical Industry.

Prediction of maize flour adulteration in chickpea flour (besan) using near infrared spectroscopy.

The present study was performed to develop Near-infrared spectroscopy based prediction method for the quantification of the maize flour adulteration in chickpea flour. Adulterated samples of Chickpea flour (besan) were prepared by spiking different concentrations of maize flour with pure Chickpea flour in the range of 1-90% (w/w). The spectra of pure Chickpea flour, pure maize flour, and adulterated samples of Chickpea flour with maize flour were acquired as the logarithm of reciprocal of reflectance (log 1/R) in the entire Visible-NIR wavelength range of 400-2498 nm. The acquired spectra were pre-processed by Ist derivative, standard normal variate, and detrending. The calibration models were developed using modified partial least square regression (MPLSR), partial least square regression and principal component regression. The optimal model was selected on the basis of highest values of the coefficient of determination (RSQ), one minus variance ratio (1-VR) and lowest values of standard errors of calibration (SEC), and standard error of cross-validation (SECV). MPLSR model having RSQ and 1-VR value of 0.999 and 0.996 having SEC and SECV value of 1.092 and 2.042 was developed for quantification of maize flour adulteration in chickpea flour. Cross validation and external validation of the developed models resulted in RSQ of 0.999, 0.997 and standard error of prediction of 1.117, and 2.075, respectively. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05456-7.

Co-extrusion of food grains-banana pulp for nutritious snacks: optimization of process variables.

Present study was undertaken to optimize the process conditions for development of food grains (maize, defatted soy flour, sesame seed)-banana based nutritious expanded snacks using extrusion processing. Experiments were designed using Box-Behnken design with banana pulp (8-24 g), screw speed (300-350 rpm) and feed moisture (14-16% w.b.). Seven responses viz. expansion ratio (ER), bulk density (BD), water absorption index (WAI), protein, minerals, iron and sensory acceptability were considered for optimizing independent parameters. ER, BD, WAI, protein content, total minerals, iron content, and overall acceptability ranged 2.69-3.36, 153.43-238.83 kg/m3, 4.56-4.88 g/g, 15.19-15.52%, 2.06-2.27%, 4.39-4.67 mg/100 g (w.b.) and 6.76-7.36, respectively. ER was significantly affected by all three process variables while BD was influenced by banana pulp and screw speed only. Studied process variables did not affected colour quality except 'a' value with banana pulp and screw speed. Banana pulp had positive correlation with water solubility index, total minerals and iron content and negative with WAI, protein and overall acceptability. Based upon multiple response analysis, optimized conditions were 8 g banana pulp, 350 rpm screw speed and 14% feed moisture indicating the protein, calorie, iron content and overall sensory acceptability in sample as 15.46%, 401 kcal/100 g, 4.48 mg/100 g and 7.6 respectively.

Optimization of food materials for development of nutritious pasta utilizing groundnut meal and beetroot.

Present study was undertaken to optimize the level of food materials viz. groundnut meal, beetroot juice and refined wheat flour for development of nutritious pasta using response surface methodology. Box-benken design of experiments was used to design different experimental combinations considering 10 to 20 g groundnut meal, 6 to 18 mL beetroot juice and 80 to 90 g refined wheat flour. Quality attributes such as protein content, antioxidant activity, colour, cooking quality (solid loss, rehydration ratio and cooking time) and sensory acceptability of pasta samples were the dependent variables for the study. The results revealed that pasta samples with higher levels of groundnut meal and beetroot juice were high in antioxidant activity and overall sensory acceptability. The samples with higher content of groundnut meal indicated higher protein contents in them. On the other hand, the samples with higher beetroot juice content were high in rehydration ratio and lesser cooking time along with low solid loss in cooking water. The different level of studied food materials significantly affected the colour quality of pasta samples. Optimized combination for development of nutritious pasta consisted of 20 g groundnut meal, 18 mL beetroot juice and 83.49 g refined wheat flour with overall desirability as 0.905. This pasta sample required 5.5 min to cook and showed 1.37 % solid loss and rehydration ratio as 6.28. Pasta sample prepared following optimized formulation provided 19.56 % protein content, 23.95 % antioxidant activity and 125.89 mg/100 g total phenols with overall sensory acceptability scores 8.71.

Development of quick cooking multi-grain dalia utilizing sprouted grains.

Multi-grain dalia (MGD) formulations were prepared utilizing sprouted wheat and mixer of other three grains (barley, sorghum and pearl millet) in the ratio of 100:0 (MGD-A), 75:25 (MGD-B), 50:50 (MGD-C), 25:75 (MGD-D) and 0:100 (MGD-E), respectively. The mixer of barley, sorghum and pearl millet was prepared using 50, 25, 25 parts of these grains, respectively. The recovery of grits/ dalia (particle size 1.41 to 2 mm) from sprouted wheat and barley was 74.56 and 69.77 %, respectively while sorghum and pearl millet yield 47.94 and 49.39 % (particle size 0.954 to 1.41 mm), respectively. Sprouting brought a reduction of cooking time by about 50 % as compared to un-sprouted studied grains. Cooking time for different MGD formulations ranged from 3.91 to 4.42 min, which was slightly increased with increasing proportion of mixer of barley, sorghum and pearl millet (p > 0.05). Rehydration ratio of MGD samples varied from 3.12 to 3.45 with minimum in MGD-E sample. Though protein content was decreased with increasing proportion of mixer of three grains in MGD samples but in vitro protein digestibility (58.68 to 62.75 %) was similar (p > 0.05). The mean overall sensory acceptability scores for MGD samples ranged from 7.50 to 8.49 with ≥8.0 in samples having up to 75 % grits of mixer of three grains. In view of very good overall sensory acceptability, rich in crude fibre, calcium and iron content and low cooking time, 25:75 parts of sprouted wheat and mixer of studied three grains, respectively may be considered for preparation of acceptable quality quick cooking multi-grain dalia.

Screw pressing performance of whole and dehulled flaxseed and some physico-chemical characteristics of flaxseed oil.

Screw pressing performance of whole and dehulled flaxseed at different seed moisture (6.4 to 11.1 % d.b.) and press head temperature (80-120 °C) was investigated. Oil recovery, residual oil, press rate and sediment content and some important physico-chemical characteristics were determined at six different levels (50, 60, 70, 80, 90 and 100 %) of dehulled flaxseed. Oil recovery decreased with increasing moisture content as well as press head temperature. Press rate was found maximum for 100 % dehulled flaxseed while minimum for 50 % dehulled flaxseed at 6.4 % moisture content. Colour of oil samples was found affected both with the level of dehulled flaxseed and press head temperature. Free fatty acids content of oil ranged from 1.07 % to 2.70 % and lower at 80 °C press head temperature. Oil and cake temperatures ranged from 53.10 °C to 65.95 °C and 69.15 to 103.75 °C, respectively. The α-linolenic acid content of different oil samples obtained at 80 °C was in the range of 53.34 ± 0.95 to 54.21 ± 1.04 %. In view of maximum oil recovery (82.9 % d.b.), lower FFA content, and oil and cake temperature, 7:3 ratio of dehulled and whole flaxseed having 6.4 % d.b. moisture content and 80 °C press head temperature may be considered for screw pressing of flaxseed.

Development of sprouted wheat based probiotic beverage.

Present study was carried out to evaluate the potential of Lactobacillus acidophilus (L. acidophilus) for development of wheat based probiotic beverage and to optimize the proportion of different ingredients viz. sprouted wheat flour, sprouted wheat bran, oat and stabilizer using response surface methodology. Acidity, pH and probiotic count of samples prepared with L. acidophilus NCDC-14 was higher than that of L. acidophilus NCDC-16 culture. Being more compatible, L. acidophilus NCDC-14 was selected for this study. Acidity (in terms of lactic acid), pH and probiotic count of the different samples ranged from 0.21 to 0.45 %, 4.0 to 4.9, and 8.30 to 10.95 log10 cfu mL(-1), respectively. Probiotic count increased with increasing amount of sprouted wheat and oat. Optimized levels for sprouted wheat flour, oat, wheat bran and guar gum were 7.86, 5.42, 1.42 and 0.6 g, respectively per 100 mL of water. Optimized probiotic beverage provided 13.19 % total solids, 1.19 % protein, 0.33 % fat, 0.10 % ash, 0.42 % crude fibre, 1.45 mg iron, calcium 15.74 mg, 11.56 % carbohydrates, 54 kcal calories and 10.43 log10 cfu mL(-1) probiotic count. Thus, Lactobacillus acidophilus NCDC-14 can be used for development of potentially probiotic beverage with sprouted wheat and oat.

Effect of chemical pretreatment on dehulling parameters of flaxseed (cv. Garima).

In the present study, effects of chemical (ethanol, HCl and sulphuric acid) pretreatment on various dehulling parameters of flaxseed (cv. Garima) including yield, hull, hullability, extraction rate and embryo (dehulled flaxseed) recovery were studied. Pretreated flaxseed, at 3.1 to 3.6 % moisture range (p > 0.05) were dehulled for 60 s in a laboratory model rice polisher/dehulling machine at 2,000 rpm followed by aspiration (hull separation) using a laboratory model aspirator. The study revealed that chemical pre-dehulling treatment of flaxseed plays a significant role in the embryo recovery of flaxseed. Both ethanol and HCl pre-dehulling treatment enhanced but sulphuric acid pretreatment reduced the embryo recovery of flaxseed. Moreover, HCL and Sulphuric acid deteriorated the quality of hull obtained during dehulling, hence may not be considered for flaxseed dehulling. The study showed the maximum embryo recovery from ethanol pretreated flaxseed, hence ethanol pre-dehulling treatment with 2 h tempering time may be considered for effective flaxseed dehulling.

Development of omega-3 rich energy bar with flaxseed.

Energy bar sample were prepared with different levels of flaxseed (0-20%) in addition to cereals and pulses with varying levels of sweeteners (45, 50, and 55%) to deliver a nutritious food to the consumer. The developed bars were evaluated for textural, colour, nutritional quality, sensory attributes and total microbial load. Different levels of flaxseed and sweeteners significantly affected the hue and chroma values of the energy bar. In general the level of flaxseed in energy bar did not affect the hardness but it was decreased with increasing level of sweeteners except in control sample. The total calories obtained from the energy bar showed significant increase with the increasing levels of flaxseed, the maximum (397.95 kcal) being for bars with 20% flaxseed and 45% sweeteners. This energy bar sample also showed the maximum protein (12.41%), crude fat (11.86%), ash (1.65%), iron (3.77 mg/100 g), crude fiber (2.18%) and omega-3 as alpha-linolenic acid (22.50%, fatty acid basis) content. The overall mean sensory score for overall acceptability for samples with 10% flaxseed and 55% sweeteners and 15% flaxseed and 45% sweeteners were at par but the omega-3 and other nutrients in the later sample was higher than the former sample, hence, 15% flaxseed and 45% sweeteners along with other ingredients may be considered for production of acceptable quality omega-3 fatty acid rich energy bar at commercial scale, which also stored well at refrigerated condition.

Flaxseed: a potential source of food, feed and fiber.

Flaxseed is one of the most important oilseed crops for industrial as well as food, feed, and fiber purposes. Almost every part of the flaxseed plant is utilized commercially, either directly or after processing. The stem yields good quality fiber having high strength and durability. The seed provides oil rich in omega-3, digestible proteins, and lignans. In addition to being one of the richest sources of α-linolenic acid oil and lignans, flaxseed is an essential source of high quality protein and soluble fiber and has considerable potential as a source of phenolic compounds. Flaxseed is emerging as an important functional food ingredient because of its rich contents of α-linolenic acid (ALA), lignans, and fiber. Lignans appear to be anti-carcinogenic compounds. The omega-3s and lignan phytoestrogens of flaxseed are in focus for their benefits for a wide range of health conditions and may possess chemo-protective properties in animals and humans. This paper presents a review of literature on the nutritional composition of flaxseed, its health benefits, and disease-prevention qualities, utilization of flaxseed for food, feed, and fiber, and processing of flaxseed.

Effect of storage on quality of fortified Bengal gram sattu.

Fortified Bengal gram sattu was prepared following standardized sattu making procedure and fortified as per FDA using wheat flour with thiamin, riboflavin, niacin, Ca and Fe and stored at 25°C, 65% RH and 35°C, 65% RH and at ambient condition (16-39°C, 18-98% RH) in low density polyethylene and laminated aluminum foil pouches. Alcoholic acidity increased by 0.04% in different sattu samples during 180 days storage but was within the acceptable limit as per BIS standard. Free fatty acids content (as oleic acid) also increased from 0.06% (in fresh) to 0.14%; however it did not affect sensory acceptability of sattu stored under different conditions. Protein digestibility, Ca and Fe contents in fortified samples were 80.6%, 170.1 and 12.5 mg/100 g, as against 80.6%, 69.5 and 10.2 mg/100 g, in control sample respectively. Storage temperatures and packaging materials did not affect the overall quality of fortified sattu except moisture content and total microbial load during 6 months storage. Fortified Bengal gram sattu, both fresh and stored, were within the acceptable sensory quality when used in the drink form.

Effect of moisture content and residence time on dehulling of flaxseed.

Effects of moisture content and residence time on various dehulling parameters of flaxseed including yield, hull, hullability, extraction rate and embryo (dehulled flaxseed) recovery were studied. A laboratory model rice polisher/ dehulling machine and a laboratory model aspirator were used for dehulling and aspiration (hull separation), respectively. The dehulling experiments were carried out for moisture contents ranging from 1.9 to 7.8% wb and residence times from 20 to 50 sec in dehulling machine at 2000 rpm of abrasive disc (rotor) of the polisher. Both moisture content and residence time played an important role in dehulling of flaxseed. The optimum moisture range and residence time for dehulling of flaxseed were 1.9 to 4.5% wb and 40 sec, respectively.

Surface Kinetics of Copper Oxidation Investigated by In Situ Ultra-high Vacuum Transmission Electron Microscopy.

We review our studies of the initial oxidation stages of Cu(001) thin films as investigated by in situ ultra-high vacuum transmission electron microscopy. We present our observations of surface reconstruction and the nucleation to coalescence of copper oxide during in situ oxidation in O2. We have proposed a semi-quantitative model, where oxygen surface diffusion is the dominant mechanism of the initial oxidation stages of Cu. We have also investigated the effect of water vapor on copper oxidation. We have observed that the presence of water vapor in the oxidizing atmosphere retards the rate of Cu oxidation and Cu2O is reduced when exposed directly to steam.