Domestic Processing Methods Research Articles

Cooking methods of Brassica rapa affect the preservation of glucosinolates, phenolics and vitamin C

Cooking Brassica vegetables as a domestic processing method has a great impact on health-promoting bioactive compounds: glucosinolates (GLS), flavonoids, hydroxycinnamic acids, and vitamin C. In Galicia (NorthWestern Spain), one of the most consumed horticultural crops is Brassica rapa, by using the leaves (turnip greens) and the young sprouting shoots (turnip tops) in different culinary preparations. In order to determine the effect of cooking, on turnip greens and turnip tops, bioactive GLS, flavonoids, hydroxycinnamic acids and vitamin C were analysed and simultaneously determined. The level of retention of each individual compound after cooking procedures was evaluated in the edible organs, and also in the cooking water, in order to compare their composition to a fresh uncooked control. Steaming, conventional boiling, and high-pressure cooking, traditional processing methods of this kind of vegetables, were the three domestic processing methods used in this work. Results showed that total GLS and phenolics were significantly affected by the cooking procedure and the loss rate varied among individual compounds. Steaming was the method that better preserved GLS and phenolic compounds. Conventional boiling and high-pressure cooking methods presented similar rate of losses of total GLS content (64%) and total phenolic content (more than 70%). Degradation among glucosinolate classes, aliphatic or indolic, was similar. The total flavonoids lost in turnip greens were 64% and 67% for conventional boiling and high-pressure, respectively. The main losses were caused by leaching into the cooking water. The concentration of vitamin C suffered a drastic loss in the process of sample handling and after cooking. Despite the fact that any cooking procedure affected negatively the nutritional composition of the turnip greens and tops, our results showed high retentions of individual compounds in steaming, and the lowest retentions were obtained in the traditional high-pressure cooking. High retention of health-promoting compounds in the cooking water should be considered for increasing the intake of properties of B. rapa.

Effect of various processing techniques on digestibility of starch in Red kidney bean (Phaseolus vulgaris) and two varieties of peas (Pisum sativum)

The effect of common domestic processing methods, such as splitting, soaking, boiling and pressure-cooking on the nutritionally significant starch fractions such as rapidly and slowly digestible starches (RDS and SDS), resistant starch (RS) and total starch (TS) in two legumes, Red kidney bean (Phaseolus vulgaris) and Yellow and Green peas (Pisum sativum) were studied. The legumes had comparatively high amount (>30%, dry basis) of RS. Soaking of all legumes resulted in reduced starch fractions, possibly due to leaching of soluble fractions. Ordinary cooking of soaked as well as unsoaked seeds led to a significant (P < 0.01) decrease in RS and increase in RDS, SDS and TS. Pressure-cooking led to even greater reduction in RS and a greater increase in RDS. Cooking of legumes gelatinizes the starch and opens up the starch structure which makes them vulnerable to α-amylase hydrolysis. Splitting of legumes markedly affects the digestibility as well as RS content of raw as well as processed legumes indicating that the seed coat plays a key role in the digestibility of starches in these seeds. Overall, the enzyme resistant starch fraction of legumes was rendered more digestible by all the domestic cooking methods used.

Effect of Soaking, Sprouting and Cooking on Chemical Composition, Bioavailability of Minerals and in vitro Protein Digestibility of Roselle (Hibiscus sabdariffa L.) Seed

2 Abstract: Chemical composition, bioavailability of minerals and in vitro digestibility of proteins in karkade seed (Hibiscus sabdariffa L.) as affected by soaking, sprouting and cooking were studied. The different methods showed varied deviation of nutrients and antinutrients from the raw seeds. Sprouting and cooking significantly increased protein content and decreased starch and soluble carbohydrates levels. K, Na and all the trace elements studied were decreased by processing methods. Cooking was more effective in improving bioavailability of minerals studied than soaking or sprouting. Total polyphenols reduced more by cooking, while phytic acid did not change significantly by processing. In vitro protein digestibility was significantly reduced by all processing methods, with soaking gave the highest percentage of reduction and cooking the lowest percentage. The results also indicated that domestic processing methods changed total acidity and fat acidity as well as N solubility in water and 1 M NaCl. Amino acid profile of the karkade seed indicated that sulfur amino acids and threonine are the limiting amino acids. With respect to FAO pattern, considerable proportion of the essential amino acids were retained on processing, except for lysine on soaking and sprouting and sulfur acids on sprouting and cooking.

Effect of soaking and hydrothermal processing methods on the levels of antinutrients and in vitro protein digestibility of Bauhinia purpurea L. seeds

The effects of various domestic processing methods such as soaking, cooking and autoclaving on the levels of certain antinutritional factors and in vitro protein digestibility of seeds of Bauhinia purpurea L., an underutilised legume collected from South India, were investigated. The raw seeds were found to contain antinutritional factors like total free phenolics (2.75 g/100 g), tannins (2.35 g/100 g), phytic acid (692 mg/100 g) and flatulence factors, raffinose (0.54 g/100 g), stachyose (1.17 g/100 g) and verbascose (0.95 g/100 g). Soaking the seeds in distilled water caused maximum reduction in the phytic acid content (37%), whereas soaking in NaHCO 3 solution reduced significant levels of phenolics and tannins (72% and 78%, respectively). A reduction in the levels of oligosaccharides (raffinose by 63%, stachyose by 42% and verbascose by 79%) was observed during cooking. Of the attempted treatments, autoclaving appeared to be most effective in reducing levels of all the investigated antinutrients, except phytic acid, and also improved the in vitro protein digestibility of B. purpurea seeds.

Effect of fenugreek flour blending on physical, organoleptic and chemical characteristics of wheat bread

PurposeWheat is considered nutritionally poor, due to deficiency of essential amino acids such as lysine and threonine, whereas fenugreek (Trigonella faenum graecum L.) flour has a high protein content (25 per cent), lysins (5.7g/16gN), soluble (20 per cent) and insoluble (28 per cent) dietary fibre besides being rich in calcium, iron and beta‐carotene. Fenugreek seeds contain 20 per cent soluble fibre (gum), which can act as functional agent in wheat dough. The presence of bitter saponins in fenugreek seeds limits their acceptability in foods. However, it has been possible to debitter fenugreek seeds by using various domestic processing methods. Therefore, their use can be exploited as functional and nutritional food as well as therapeutic agents. Hence, in the present study efforts have been made to develop wheat‐fenugreek‐based health bread.Design/methodology/approachIn commonly grown varieties of wheat, namely WH‐423, and fenugreek namely Pusa, early bunching was obtained. Fenugreek seeds were divided into three portions. One portion was left unprocessed (raw), while the other two portions were soaked (12hr at 37○C) and germinated (48hr at 37○C) separately. Soaked and germinated samples were dried at 55‐60○C. Dried samples of raw, soaked and germinated seeds were ground to fine powder. Fenugreek seed powder (raw, soaked and germinated) was blended separately with wheat flour at different levels, namely 5, 10, 15 and 20 per cent. Breads from control and supplemented flours were baked in replicates. Baking, organoleptic and nutritional characteristics were analysed in the control and supplemented breads. The data were statistically analyzed in complete randomized design for analysis of variance according to the standard method.FindingsSupplementation of wheat flour with fenugreek flour from 5 to 20 per cent levels increased the protein, lysine, minerals and fibre contents of bread. Additions of fenugreek (raw, soaked and germinated) up to the level of 15 per cent produced bread with a satisfactory loaf volume and other sensory quality attributes (crumb colour, crumb texture, taste etc.), whereas the 20 per cent level of supplementation caused a depression effect in loaf volume and the breads were found to be bitter in taste, However, among the various supplemented breads, germinated fenugreek flour‐supplemented bread at 15 per cent level showed satisfactory baking and organoleptic characteristics and contained an appreciable amount of protein (24 per cent), total lysine (3.02g/100g protein), dietary fibre (12.04 per cent) and minerals.Practical implicationsFast food are becoming as popular, as in developing countries. Keeping this fact in view, in the present study, health breads were prepared. The developed product had good acceptability, was nutritionally rich and had therapeutic value. So, these can be considered for commercialization.Originality/valueAs fenugreek seeds contain 20 per cent soluble fibre (gum), and 5.7g/16gN lysine contents, the soluble fibre of fenugreek seeds has been reported to reduce blood sugar and cholesterol levels. Therefore, their use can be exploited in the development of health foods.

Effect of domestic processing and cooking methods on total, HCl extractable iron and in vitro availability of iron in bathua and fenugreek leaves.

Effect of domestic processing and cooking methods on total, HCl extractable iron and in vitro availability of iron in bathua and fenugreek leaves.

Content of phytic acid and HCl-extractability of calcium, phosphorus and iron as affected by various domestic processing and cooking methods

ICPL-87, the high yielding cultivar of pigeon pea (Cajanus cajan) released by ICRISAT (International Crop Research Institute for Semi-Arid Tropics), India was subjected to various domestic processing and cooking methods, i.e. soaking (6, 12, 18 h, 30°C), soaking (12 h) and dehulling, ordinary as well as pressure cooking and germination (24, 36 and 48 h, 30°C). The unprocessed seeds of this variety contained considerable amounts of phytic acid, (857 mg per 100 g). This was reduced significantly (P<0.05) by 6–28%, 30%, 4–32%, 4–36%, 35–45% in soaked, soaked-dehulled, ordinary as well as pressure cooked and germinated seeds, respectively. Except for soaking and dehulling, the remaining processing and cooking methods did not lower the contents of total calcium, phosphorus and iron. HCl-extractability of these dietary essential minerals, an index of their bioavailability, was enhanced significantly when the pigeon pea seeds were processed and cooked, possibly due to reduction in phytate content, which is known to chelate the minerals. A significant and negative correlation between the phytic acid and HCl-extractability of minerals further strengthens these findings.

Effect of domestic processing and cooking methods on total, hcl extractable iron and in vitro availability of iron in spinach and amaranth leaves.

Spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves were stored in polyethylene bags and without packing for 24 and 48 hours in a refrigerator at 5 degrees C and 30 degrees C in polyethylene bags. The fresh leaves were also dried (oven and sun), blanched (5, 10 and 15 min) and cooked in an open pan and a pressure cooker. The processed leaves were analysed for total iron, its availability and antinutrient content. The iron content of these leaves varied from 26.54 to 34.14 mg/100 g, dry weight and its HCl-extractability and in vitro availability were 62.11-67.18% and 3.03-3.97% of total respectively. Drying and storage had no significant effect on total iron content, HCl-extractability and availability (in vitro), while blanching and cooking resulted in significant improvement of iron availability, and a significant reduction in oxalic acid content, while only blanching significantly reduced phytic acid and polyphenol contents. Thus cooking and blanching are good ways to improve HCl-extractability and in vitro availability of iron.

Changes in phytates and HCl extractability of calcium, phosphorus, and iron of soaked, dehulled, cooked, and sprouted pigeon pea cultivar (UPAS-120).

UPAS-120, a high yielding and early maturing variety of pigeon peas released by the Department of Plant Breeding, CCS Haryana Agricultural University, Hisar contained a significant amount of phytic acid, i.e. 886 mg/100 g. When it was subjected to various domestic processing and cooking methods viz. soaking (6, 12, 18 h), dehulling, ordinary as well as pressure cooking and germination (24, 36 and 48 h), a drastic decrease in level of phytic acid with a remarkable increase in the HCl-extractability of mono, divalent, and trivalent ions, like calcium, phosphorus, and iron occurred. Germination (48 h) was found to be the best method for decreasing the phytic acid content, i.e. 35 to 39 percent less than the control and significantly (p < 0.05) increasing the non-phytate phosphorus and HCl-extractable phosphorus. Pressure cooking of soaked-dehulled pigeon pea also rendered equally good results. The calcium, phosphorus, and iron contents of pigeon pea seeds were 197.3, 473.1, and 9.91 mg/100 g, respectively; some losses varying from 3 to 9 percent were noticed when the legume was subjected to soaking, cooking, and germination but the maximum losses, i.e. 23 percent, occurred when the seeds were dehulled. However, HCl-extractability of Ca, P, and Fe improved to a significant extent when the pigeon pea seeds were soaked, soaked-dehulled, cooked and sprouted which may have been due to decrease in the phytate content followed by processing and cooking. The significant negative correlations between the phytic acid and HCl-extractability of minerals of processed pigeon pea strengthens these findings.

HCl-extractability of minerals from ricebean and fababean: influence of domestic processing methods

HCl extractable mineral soluble in 0.03 N HCl the concentration of HCl found in human stomach is an index of its bioavailability from foods. The amount of HCl-extractable calcium, phosphorus and iron in raw and unprocessed seeds of rice bean and fababean were (70.2, 55.2), (78.0, 71.2) and (33.4, 35.1), respectively. Among all the domestic processing methods, sprouting was the best method followed by dehulling and soaking (12 h) for improving the extractability of Ca, P and Fe whereas did not affect the total mineral contents. The husks of these legumes had significantly lower levels of extractable Ca, P and Fe.

Effect of various domestic processing methods on antinutrients and in vitro protein and starch digestibility of two indigenous varieties of Indian tribal pulse, Mucuna pruriens Var. utilis.

The effect of various domestic processing methods on antinutrients and starch fractions and in vitro protein and starch digestibilities of white and black varieties of Mucuna pruriens var. utilis was studied. Cooking or autoclaving of both raw seeds and presoaked seeds in different solutions (water, tamarind extract, sodium bicarbonate, and citric acid) significantly (p < 0.05) reduced the content of total phenolics, phytic acid, trypsin inhibitor and chymotrypsin inhibitor activities, and L-dopa compared to soaking or dry heating techniques. The germination processes (24 and 48 h) were also effective in the reduction of various antinutrients, although this reduction appeared to be more pronounced in a prolonged period of germination (72 h). Water soaking followed by dehusking was found to be ineffective in the reduction of trypsin and chymotrypsin inhibitor activities in both varieties. All of the treatments were effective in significantly (p < 0.05) reducing the resistant starch content in the presently investigated samples. Cooking as well as autoclaving brought about a more significant (p < 0.05) improvement in the digestibility of protein and starch compared to germination and dry heat treatment. Moreover, among the different processing techniques, soaking in sodium bicarbonate solution followed by cooking (29.6-34.8%) or autoclaving (33.0-37.2%) seemed to be the best method for improving starch digestibility.

Saponin content and trypsin inhibitor activity in processed and cooked pigeon pea cultivars

Four high-yielding varieties of pigeon pea namely UPAS-120, Manak, JCPL-151. ICPL-87 had considerable amounts of antinutrients i.e. saponins and trypsin inhibitors. Saponin content of these unprocessed cultivars ranged from 2164 to 3494 mg/100 g. There were significant varietal variations in trypsin inhibitor activity (1007–1082 TIU/g) of these pigeon pea cultivars. Some simple, inexpensive and easy-to-use domestic processing and cooking methods, namely, soaking (6, 12, 18 h), soaking (12 h)-dehulling, ordinary cooking, pressure cooking and germination (24, 36, 48 h) were found to be quite effective in lowering the level of saponins and trypsin inhibitors in all the pigeon pea cultivars. Pressure cooking of soaked and dehulled seeds lowered the content of saponins to a maximum extent (28 to 38%) followed by ordinary cooking of soaked and dehulled seeds (28 to 35%), soaked dehulled raw seeds (22 to 27%) and 48 h germinated seeds (15 to 19%). Loss of TIA was marginal due to soaking but ordinary as well as pressure cooking of unsoaked and soaked-dehulled pigeon pea seeds reduced the TIA drastically. Pressure cooking of pigeon pea seeds completely destroyed the TIA while it was reduced to the extent of 86–88% against the control in 48 h pigeon pea sprouts.

Effect of domestic processing and cooking methods on the carbohydrate contents of newly released moth bean (Phaseolus aconitifolius Jacq.) cultivars.

Three newly high yielding cultivars, Jwala, RMO 225 and RMO 257, together with one local variety commonly used by the farmers of the area were studied.

Quantification of Quercetin in Onion (Allium Cepa) after Domestic Processing

The flavonol quercetin has been reported as having many health benefits, including a reduction in the risk of developing cardiovascular disease, stroke, and some types of cancer. The overall content of quercetin in onion was examined in four yellow varieties (`Rio Rita', `RNX 10968', `Predator', and `Tamara') and one red variety purchased at a local grocery store. Each bulb was quartered, with one quarter saved as a control and the other three quarters subjected to three cooking treatments that simulated common domestic processing methods of preparing onion. The treatments included sautéing in sunflower oil for 5 minutes at 93 °C, baking for 15 min. at 176 °C, and boiling for 5 minutes in distilled water. Samples were frozen in liquid nitrogen, ground to a fine powder, blended with 80% EtOH, and filtered for quercetin extraction. The filtrate was then analyzed with a spectrophotometer (uv 374 nm). Quercetin concentrations were obtained in mg quercetin/kg fresh weight of tissue by regressing spectrophotometer readings onto a standard curve. Significant differences between varieties were found when examining fresh samples alone with the red variety containing the highest content of quercetin. Results of cooking showed that sautéing produced an overall 27% gain in quercetin concentration (significantly higher than the fresh control), baking produced an overall 4% gain in concentration (insignificant from the fresh control), while boiling produced an overall 18% loss in quercetin concentration (significantly lower than the fresh control).

Effect of domestic processing methods on the starch, non-starch polysaccharides and in vitro starch and protein digestibility of three varieties of rice with varying levels of amylose

The effect of processing on the in vitro protein and starch digestibility of three varieties of rice ( Doongara, Inga and Japonica) with different levels of amylose was studied. The effect of heating processes on the amount of protein, amylose, total starch, and non-starch polysaccharide (NSP) and resistant starch (RS) contents was also analysed. Results indicated a highly significant increase in the protein and starch digestibilities of rice. Pressure-cooking rendered starch and protein more digestible. The levels of amylose affected the digestibility of starch, but not protein digestibility per se. Boiling and pressure-cooking caused only small changes in the total RS and NSP contents in all the three varieties but some redistribution from insoluble to soluble components was observed.

Optimum Domestic Processing and Cooking Methods for Reducing the Polyphenolic (Antinutrient) Content of Pigeon Peas

Four high yielding and early maturing cultivars of pigeon pea (Cajanus cajan) namely UPAS-120, ICPL-87, ICPL-151 and, especially, Manak, contained significant amounts of polyphenols (1075 to 1328 mg/100g), which may limit their utilization. The effectiveness of soaking (6, 12 and 18 h, 30 degrees C), soaking and dehulling, ordinary cooking, pressure cooking and germination (24, 36, 48 h, 30 degrees C) in reducing the levels of polyphenols was investigated. A decrease in the polyphenolic contents varying from 4 to 26 percent in different pigeon pea cultivar was achieved. Pressure cooking of soaked-dehulled seeds was found to be the most effective method, followed by sprouting for 48 h, ordinary cooking of soaked-dehulled seeds, and pressure cooking of soaked whole seeds followed by sprouting for 36 h.

Effect of home processing on ascorbic acid and ?-carotene content of spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves

The present investigation was conducted to study the concentration of ascorbic acid and beta-carotene in spinach and amaranth leaves as affected by various domestic processing and cooking methods which included storage of leaves in polythene bags or without packing for 24 and 48 hours in refrigerator at 5 degrees C; at 30 degrees C in polythene bags; drying (sun and oven); blanching (5, 10, 15 min); open pan and pressure cooking. Ascorbic acid content of fresh leaves was 624.1 to 629.0 mg and beta-carotene content was 35.3 to 53.1 mg/100 g dry weight. The percent loss of ascorbic acid ranged from 1.1 to 6.3 and 55.3 to 65.9 while lower losses (0.0 to 1.3 and 1.5 to 2.1) of beta-carotene were observed in leaves stored in refrigerator and at 30 degrees C, respectively. A markedly greater reduction in ascorbic acid and beta-carotene was observed in dried, blanched and cooked leaves. The study recommended the storage of leaves in refrigerator, drying in oven, blanching for shorter time and cooking in pressure cooker for better retention of these two vitamins.

Effect of various domestic processing and cooking methods on the HCl‐extractability of minerals from pea seeds

AbstractVarious domestic processing and cooking methods like soaking (6, 12 and 18 h), dehulling of soaked pea seeds, ordinary and pressure cooking of unsoaked, soaked and soaked‐dehulled pea seeds and sprouting for varying periods (12, 24 and 48 h) brought about a significant (P &lt; 0.05) improvement in HCl‐extractability of minerals, an index of their bioavailability to the human system. Sprouting was noticed to be the best processing method followed by pressure cooking and ordinary cooking of soaked‐dehulled pea seeds for remarkably enhancing the availability of dietary essential minerals i.e. calcium, phosphorus, iron, copper and zinc.

Effect of domestic processing and cooking methods on in-vitro starch digestibility of different pea cultivars ( Pisum sativum)

There were significant ( P < 0·05) varietal differences in the starch digestibility ( in vitro) and contents of reducing sugars, non-reducing sugars, and starch in four cultivars of field as well as vegetable peas. Various domestic processing and cooking methods, including soaking for 6, 12 and 18 h, soaking (12 h) followed by dehulling, ordinary and pressure cooking of unsoaked, soaked and soaked-dehulled seeds, and sprouting for varying periods, i.e. 12, 24 and 48 h, brought about significant increase in starch digestibility of peas. Pressure cooking was found to be the most effective method followed by ordinary cooking, sprouting, dehulling and soaking. Cooking may gelatinise starch and sprouting may mobilise starch, thereby resulting in improved starch digestibility by pancreatic amylase.

Digestibility of proteins and starch (in vitro) of amphidiploids (black gram x mung bean) as affected by domestic processing and cooking.

The effects of different domestic processing and cooking methods on starch digestibility (in vitro) and protein digestibility (in vitro) of four strains of amphidiploids (black gram x mung bean) were investigated. An increase of 35 to 48% and 22 to 25% was observed in starch digestibility and protein digestibility, respectively, when the seed of amphidiploids were soaked for 18 h. Cooking (both of unsoaked and soaked seeds) and germination improved significantly the starch digestibility and protein digestibility of all the varieties.