COMPARATIVE STORAGE STUDIES ON THE ORGANOLEPTIC ATTRIBUTES OF IRON FORTIFIED WHOLE WHEAT FLOUR

Transcription

1 Sarhad J. Agric. Vol. 23, No. 4, 2007 COMPARATIVE STORAGE STUDIES ON THE ORGANOLEPTIC ATTRIBUTES OF IRON FORTIFIED WHOLE WHEAT FLOUR Sahib Alam *, Majid Suhail Hashmi **, Abdul Sattar Shah ** and Umbreen Latif Khan * ABSTRACT A three months storage study was carried out on the stability of whole wheat flour fortified with iron through small scale local grinders called Chakkies during 2004 at NWFP Agricultural University Peshawar. The Chakkies were equipped with iron premix feeders. Fortified and unfortified (control) wheat flour samples of the same lot were packed in tin boxes, polypropylene (PP) woven bags and gunny bags of 2 kg capacity each and stored under ambient room conditions (room temp C and RH 43-66%) for three months (April to July, 2004). From each type of flour chapattis were backed by traditional method at the beginning (0-day) and monthly intervals for a total period of three months. Organoleptic evaluation of these chapattis was carried out by a panel of trained judges. Score for appearance of both types of breads decreased during storage but remained in acceptable limits (P>0.01) however the effect of packaging material was found non significant. A similar trend was found for texture and odor of both types of breads. Folding ability and overall acceptability of breads made from iron fortified and unfortified wheat flour was significantly affected by both storage intervals and packaging materials, however no variation was found within flour types. The study provides an indication of better suitability of iron fortified and unfortified chakki wheat flour for a storage period of not more than 60-days. Keywords: Fortification, Storage stability, Sensoric evaluation, Whole wheat flour INTRODUCTION Iron deficiency is the most common nutritional disorder in the world. A number of strategies are followed world wide to combat Iron Deficiency Anemia (IDA) among vulnerable groups. Only food fortification with iron is the proven way for the alleviation of iron deficiency anemia. In Pakistan, with regard to fortification, wheat flour is the ideal vehicle because it is commonly consumed in large and relatively constant amounts by all age groups. It is estimated that in Pakistan per capita consumption of wheat is 124 kg per year or 340 grams per day. Domestic consumption of wheat for was estimated to be 21.5 millions metric tons. Wheat consumption for food purposes is annually growing at a rate of about 3 % (Khan, 2001). Wheat is the cheapest and major source of proteins and calories. The net dietary protein calories of wheat bread is 5.9% and can provide the daily need of protein for adults if consumed in an adequate amount (Khan and Eggum, 1978). Wheat is a good source of vitamins B 1, B 2, B 6, niacin as well as iron and zinc in its natural state. But since most of these nutrients are concentrated in the outer layer of wheat grain, a significant portion is lost during roller milling process. For more refined wheat flour, the loss of minerals and vitamins is greater as in modern milling sector. The nutrients in wheat flour are carbohydrates, protein, lipid, vitamins and minerals. These nutrients are mostly concentrated in bran, germ and outer endosperm of wheat grain (Kent, 1983). Phytic acid (inositol hexaphosphric acid) is another substance which is associated with the bran of wheat. This substance form insoluble complexes with divallent and trivalent metallic ions such as Zn -2, Ca ++, Cu ++, and Fe ++ and Fe +++ which are not absorbed in gastrointestinal tract and there by lowers the bioavailability of essential elements leading to deficiency diseases and also reduces nutritive value of cereals (Smith and Circle,1978). More than 90% of total phytic acid of wheat is localized in bran (Pringle, 1952). Therefore, in whole wheat flour, which contains bran, phytic acid tends to immobilize the calcium and iron present in the flour itself and in other ingredients of diet as well. Flour is the main defined product of wheat after milling. In Pakistan there are two types of milling sectors. The modern and sophisticated type is the roller flour mills which grind approximately 45% of the total wheat consumed in the country. The other type is the small scale grinders or village based Chakkies which grinds about 55% of the wheat flour consumed in the country. In Pakistan 80% wheat is consumed in the form of chapattis. There are different types of chapattis such as tandoori roti, khameeri roti or leaven bread and Nan (Aziz and Bhatti, 1962). Flours of fine granularity yield chapattis of superior quality (Kent, 1983) The hazards to flour storage include mould and bacterial attack, insect infestation and oxidative rancidity and eventually deteriorating backing quality. The optimum moisture content for storage of flour must be interpreted in relation to length of storage envisaged, and to the prevalent ambient temperature and relative humidity. * Department of Agricultural Chemistry, NWFP Agricultural University, Peshawar - Pakistan ** Food Technology Section, Agricultural Research Institute, Tarnab, Peshawar - Pakistan

2 Sahib Alam et al. Comparative Storage Studies on Organoleptic Attributes of iron 1122 Due to iron fortification the flour is likely to have different nutritional characteristics, microbiological load, organoleptic properties and storage behavior than those of unfortified wheat flour. Study therefore was undertaken to evaluate and compare the storage stability and nutritional quality of both types of flours for adapting whole wheat flour as an ideal vehicle for iron fortification to eradicate Iron Deficiency Anemia from the country. MATERIALS AND METHODS The present research was carried out in the Department of Agricultural Chemistry NWFP Agricultural University, Peshawar during Whole wheat flour (100% extraction) samples which were fortified with premix containing ferrous sulfate, ethylenediamine tetraacetic acid and folic acid (20.0:20.0:1.5 ppm) were obtained from local Chakkies equipped with microfeeders in village Malakandher, district Peshawar and packed in different packaging materials viz. tin boxes, polypropylene bags and gunny bags. The samples were stored in postgraduate lab of the department of Agricultural Chemistry, NWFP Agricultural University, Peshawar for a storage period of three months. Samples were analyzed at the beginning of the experiment and at monthly intervals for various parameters. Three replications per treatment were taken at each storage interval for analysis. Breads (Naans) were prepared by traditional methods at each storage intervals and evaluated for organoleptic characteristics. Preparation of Naans Preparation of Naan of both types of flour (i.e. unfortified and fortified with iron premix) was carried out by traditional methods. WWF (100 g), yeast (0.4 g), sugar (0.5 g), sodium bicarbonate (0.8 g), salt (1.8 g), oil (1.5 ml) and water (73 ml) were mixed into dough (Rehman et al. 1983). The amount of water required was determined by farinograph method (Rehman et al. 2003). The dough was kneaded for 10 min (4 min [slow] + 6 min [fast]) with a Hobart mixer (model A-200, H , Hobart Corp., Troy, OH) equipped with a dough-kneading arm. After mixing, the dough was allowed to ferment for 1 h at 30 C. A dough ball of 90 g was taken and sheeted into a disk of 7-in. diameter with rolling pin. The disk was pressed with the fingertips in the center covering 5-in. diameter, was allowed to proof for 15 min and was baked in a tandoor (mud oven). The naans (two) were packed in a polyethylene bag at 32 C (Farooq et al. 2001). Organoleptic Evaluation The sensory evaluation of breads prepared from both iron fortified and unfortified wheat flour was carried out using the 9- point hedonic scale method of Larmond (1977). The breads were presented to a taste panel of judges for organoleptic valuation. The judges were explained the procedure for evaluation and were trained on the subject of sensory evaluation and giving appropriate score to the samples. Efforts were made to make sure that the same judges evaluate the products at each storage interval. They were asked to evaluate the breads for appearance, texture, odor, folding ability and overall acceptability was calculated as mean score given by a judge for these parameters according to 9- points hedonic scale. Statistical Analysis Data were analyzed using three factors CR Design (Steel et al, 1997). Means were separated using LSD for the comparison of treatment means. The data related to fortified and unfortified flour was analyzed for their means comparison with T- Test. All the statistical analysis was completed by M- State-C Ver.2, computer program for statistic. RESULTS AND DISCUSSION Appearance Appearance of bread (Table-I) was significantly (P<0.01) influenced by storage, however effect of packing material was found to be statistically nonsignificant. The preferences of judges decreased with each storage interval. All the breads prepared from fortified flour were given scores lower than the control samples. However, differences were non-significant. It is however noteworthy that although the scores decreased with storage, they remained with in the acceptability limits (>5). Texture The score for texture showed similar trend as in appearance (Table-II). The quality significantly (P < 0.01) deteriorated with progressive storage of the flour. The mean values ranged from 7.50 (0-day) to 5.72 (at 3-months storage). Effect of packing material was non-significant with the mean scores got for this parameter were 6.66 for sample stored in Tin boxes, 6.62 for samples stored in polypropylene woven bags and 6.46 for samples stored in Gunny bags. Although the scores decreased with storage, they remained with in the acceptable limits (P>5). Odor Odor was significantly influenced by storage (Table-III), however the effect of packing material was found to be statistically non-significant on this parameter of Naans. All the fortified breads were rated lower than the control; however the overall scores for all the samples remained in the acceptable range (>5). Folding Ability Folding ability is an important sensoric quality attribute of flat bread. It shows the characteristic

3 Sarhad J. Agric. Vol. 23, No. 4, elasticity, specific for flat bread. Naans with low folding ability is not considered as good bread. The mean of the scores given to Naans by the judges for folding ability was 7.67 at 0 day evaluation (Table- IV). With each successive storage period the scores decreased gradually but significantly (P 0.01). The values were 6.83, 6.33 and 5.67 at 30, 60 and 90- days of storage intervals, respectively. Types of packing materials used for storing the flour significantly (P 0.01) influenced the folding ability of the resultant Naans with Tin boxes giving higher average score than polypropylene and gunny bags. Chappatties prepared from control samples got higher average score than Naans prepared from fortified wheat flour. Overall the scores for all the samples remained in the acceptable range (>5). Overall Acceptability Data (Table-V) regarding overall acceptability of iron fortified and unfortified wheat flour showed that this attribute was significantly influenced by both storage and packing material. Samples stored in Tin boxes got higher score (6.94) followed by polypropylene bags (6.66) and gunny bags (6.60). The average values during storage for overall acceptability of all the Naans were 7.67, 6.92, 6.49 and 5.85 for the 0, 1, 2 and 3 months respectively and it has been observed that as the average time of flour increases its overall acceptability decreases. Deterioration of the sensoric value of the flours began slowly and unpleasant taste was developed during the third month of storage period. Samples of the experimental flours had been stored in tin boxes, polypropylene woven bags and gunny bags. Polypropylene woven bags and gunny bags have fairly large pores and are permeable to air, oxygen and moisture. It is noteworthy that the storage months (April-June) of this experiment were the most inclement months of the year with highest average temperature and relative humidity. Flour being hygroscopic in nature, absorbed moisture from atmosphere and became a good medium for microbial growth. There was a progressive increase in the fungal count and a concomitant fall in the organoleptic properties. Similar results were reported by Khan et al. (2002) for storage of flour in permeable packing materials. Oxidation and heat damage to starch and fats also cause deterioration of flour quality. Another reason for this effect is due to anaerobic bacteria or wheat flour amylases as were observed by Deveighere et al. (2002). Associated with lipid deterioration are losses of carotenoids and Vitamin E (Galliard, 1983). It has also been reported that flour stored in air permeable material is subject to the production of acidity due to the action of microbial fermentation (Khan et al. 2002). CONCLUSION AND RECOMMENDATIONS It can be concluded from the results that the suitability of flour of both types decreases with storage beyond two months. Although the organoleptic qualities of flour remain within acceptable limits, the acceptability decreases almost linearly with storage time. Table.I Appearance of bread made from iron fortified and unfortified wheat flour stored in different packaging materials at different storage intervals Storage Tin boxes Polypropylene bags Gunny bags Mean 0-days a 30-days ab 60-days b 90-days b Mean Overall Mean 7.25a 6.54a 6.79a Table.II Texture of bread made from iron fortified and unfortified wheat flourstored in different packaging materials at different storage intervals. Storage Tin Boxes Polypropylene bags Gunny bags Mean 0-days a 30-days b 60-days b 90-days c Mean Overall Mean Means in rows and columns followed by the same letters are not significantly different (P 0.01)

4 Sahib Alam et al. Comparative Storage Studies on Organoleptic Attributes of iron 1124 Table.III Odor of bread made from iron fortified and unfortified wheat flour stored in different packaging materials at different storage intervals Storage Tin Boxes Polypropylene bags Gunny bags Mean 0-days a 30-days ab 60-days b 90-days c Mean Overall Mean Table.IV Folding ability of bread made from iron fortified and unfortified wheat flour stored in different packaging materials at different storage intervals Tin Boxes Polypropylene bags Gunny bags Mean 0-days a 30-days b 60-days c 90-days d Mean Overall Mean 6.92a 6.58b 6.38c Table.V Overall acceptability of bread made from iron fortified and unfortified wheat flour stored in different packaging materials at different storage intervals Tin Boxes Plastic bags Gunny bags Mean 0-days a 30-days b 60-days c 90-days d Mean Overall Mean 6.94a 6.66b 6.60b REFERENCES Devlieghere, F. L. Vermeiren, Bocckstal and J. Debevere Study on antimicrobial activity of a food packaging material containing potassium sorbate. Acta alimentaria 29 (2) Farooq, Z., S. Rehman and M.Q. Bilal Suitability of wheat varieties/lines for the production of leavened flat bread (Naan). J. Res. Sci. 12, Galliard, T Enzymic Degradation of Cereal Lipid. Inc Lipids in Cereal Tech. Edited by Barnes, London: Academic Press, pp Kent, N.L Technology of cereals with special reference to wheat 3rd edition. Flour: , Nutritional attributes of flour and bread , , Chapattis, , published by Robert Maxwell, M.C. and printed in UK by A wheat on Co. Ltd. Exeter. Khan, A.D., E. Nusrat, M. Yasin, A. Naheed and J. Akmal Wheat flour preservation by means of packaging and its statistical evaluation. Pak. J. Sci. Industrial Res. 45 (2): Khan, M.A Pakistan wheat flour fortification with iron, situation analysis of small scale grinders. Nutrition Section, Planning and Dev. Div., Govt. of Pakistan. Food, Agric. and Livestock, Econ. Wing, Islamabad.

5 Sarhad J. Agric. Vol. 23, No. 4, Khan, M.A. and B.O. Eggum The nutritive value of some Pakistani diets. J. Sci. Food. Agric. 29: Larmond, E Method for sensory evaluation of food. Canada Deptt. of Agric. Public.1284: Pringle, W.J.S Mineral constituents of wheat and flour. It Bate-Smith, E.C. and Morris, T.N. (Eds) food, science, Cambridge Univ. Press. Rehman, S., S. A. Anjum, and F. M. Anjum Chemical, rheological and storage studies of iron fortified whole wheat flour. Pak. J. Food Sci.13, Smith, A.K. and S.J. Circle Soyabean chemiustry and technology. Avi. Public Comp. Inc. Westport Connecticut, USA. Steel, R.G.D., J.H. Torrie and D. Dickey Principles and Procedures of Statistics. A Biometrical Approach. 3rd Ed., McGraw Hill Book Co., Inc, New York. Whiteley, R Biscuit manufacture. Appl. Sci. Pub. Ltd. London.

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