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Common beans (Phaseolus vulgaris L.): Potential food as healthy diet component. Dr. Ijaz Ahmad, *Dr. K. D. Dolan and Dr. Quratulain Syed Food and Biotechnology Research Centre, PCSIR Laboratories Complex Lahore , Pakistan * Department of Food Science and Human Nutrition, MSU, USA.
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Common beans (Phaseolus vulgaris L.): Potential food as healthy diet component Dr. Ijaz Ahmad, *Dr. K. D. Dolan and Dr. Quratulain Syed Food and Biotechnology Research Centre, PCSIR Laboratories Complex Lahore , Pakistan * Department of Food Science and Human Nutrition, MSU, USA
Background • Common beans are consumed worldwide. (Nyombaire et al., 2011). • Protein, • Energy (approx. 380 kcal/100 g), • Vitamins (thiamine, riboflavin, niacin, vitamin B-6)’ • Minerals (calcium, iron, zinc, phosphorus, potassium, • magnesium), • Free unsaturated fatty acids (linoleic, linolenic) • Dietary fiber, • Phytochemicals such as flavonoids and phenolics, • Antioxidants. • (Reyes-Moreno & Paredes-Lopez, 1993), • (Boateng et al., 2008), • (Granito et al., 2008).
LOW-FAT ALTERNATIVE • In developing countries, beans may be a low-fat alternative to animal proteins and the dietary fiber in beans is mainly consists of soluble form which helps to lower cholesterol, a main risk factor for the development of cardiovascular disease. • Great potential as a healthy diet component in the developed countries also, where cholesterol and obesity have become major health issues. (Nyombaire et al., 2011).
PERFECT FOOD • Malnutrition is one of the major problems in Pakistan which is mainly due to the protein and energy deficiency in the diet. Food legumes have an important role to play in improving the quality of cereal based diets. • - Nutritionists characterize the common bean as a nearly perfect food because of its high protein content and fiber/ complex carbohydrates. • - Common bean has a very promising future in Pakistan. The use of common beans may decrease malnutrition and protein deficiency in diets, and may decrease dependence on costly animal’s proteins. (Amanullah Jr. 2010).
LIMITED USE OF LEGUMES • The consumption of legumes is limited chiefly by such factors as inadequate levels of innovation in terms of developing legume products more suited to modern lifestyles (Schneider, 2002) • - Gastric problems following consumption; • - Low sensory value; • - Time-consuming for preparation of legume-based dishes (Krupa, 2008).
PROCESSING - Processing leads to changes in color, consistency, flavor and nutritive value. (Słupski, 2012). - To improve the culinary properties and due to the presence of non-nutritive constituents, cooking is required. (Słupski and Lisiewska. 2013). - The introduction of convenient, ready to serve, easy to prepare legume products may lead to an increase in their consumption.
Materials and Methods • Soaking • 16 h at room temperature in 5 times distilled water. • To reduce the anti-nutritional factors. (Fernandes et al. 2010). • Cooking • Common Beans were cooked in water with 2% NaCl at atmospheric pressure for 60 min. • Autoclaving • Samples (275 g) and brine containing 2% NaCl were filled in cans, • Sealed (Dixie Seamer, Athens, Georgia) under vacuum (20-mm Hg) in steel cans (75 mm x 112 mm). • - Rotary steam retort (FMC Steritort Lab Sterilizer, USA) at 121oC for 10 min. • - Needle-type thermocouple (Ecklund-Harrison Tech. Inc., Florida, USA) to measure the centre temperature.
Incubation study Six cans were incubated at room temperature for 10 days and were observed for signs of swelling and changes in sensory properties at the end of the incubation period. (Dryer and Thompson, 1984) Texture analysis The textural characteristics were analyzed according to TPA with a TA.XT2i Texture Analyzer (Stable Micro Systems Ltd, London, UK). (Bourne, 1978) The bean was compressed with a 2 mm diameter TA-53 probe at a constant cross-head speed of 10 mm s-1 (distance 5 mm).
Sensory evaluation Samples were heated 70oC and presented to the panel without brine. Canned samples were compared with freshly cooked samples. Table 1. Description of the sensory parameters.
Total Phenolic Contents Total phenolic contents were determined by using methanol-80 as solvent. The results expressed as mg gallic acid equivalent (GAE)/ g. ORAC (Oxygen Radical Absorbance Capacity) The analysis was carried out following the method described by (Huang et al., 2002). The plate was incubated at 37oC for 30 min in a Microplate Reader (Biotek Instruments, Inc. Model FLX 800, Winooski, Vermont, USA).
Temperature profile in steam retort Temperature = Temp. inside the cans; Rt = Retort temp.
Texture of cooked beans Average peak force (g) = 325.76 + 19.62
Texture of canned beans Average peak force (g) = 165.09 + 17.05
Peak force (g) Effect of cooking and canning on instrumental texture.
Sensory evaluation HP = Hardness-pericarp; HG = Hardness of grain; G = Granularity.
Effect of soaking and cooking on TPC of black beans. Xu and Chang 2008. - About 75% to 79% of phenolics were leached into soaking and cooking water. - The substantial amount of phenolics is lost by cooking and discarding cooking water.
Effect of canning on TPC of common beans. - A = Loss calculated for canned beans. - B = Loss calculated for combined effect of canned beans and brine.
Effect of soaking and cooking on ORAC value of black beans. • Xu and Chang 2008. • Pressure boiling is better not only for preserving antioxidant components but also for decreasing the cooking time.
Effect of canning on ORAC value of common beans. - A = Loss calculated for canned beans. - B = Loss calculated for combined effect of canned beans and brine.
SOAKING WATER AND COOKING WATER • - There is reduction of phenolic compounds and antioxidant activity in soaked beans. • Maximum loss was found when cooking water was discarded. • Loss may be avoided by consuming the beans with cooking water. • - Discarding the soaking water before cooking was found to be advantageous. • It is also an effective way to reduce the amounts of oligosaccharides that may cause intestinal discomfort. Ranilla et al. (2009); Fernandes et al. 2010. • Thus to minimize losses of TPC and antioxidant activity it is better to consume cooking water.
Conclusion • The effects of thermal processing on antioxidants vary with the food type and thermal processing method. • Canned common beans contained substantial amounts of antioxidants. • Canning technology is useful not only for retaining TPC and antioxidant activity in the end product but also for decreasing the cooking time and fuel economy. • Cooking water becomes more viscous and is appropriate to be consumed with beans. • The potential benefits of consuming beans from nutraceutical standpoint should be emphasized. It will also help to alleviate diseases and maximize the use of beans in food industry.