Original Research Article Nutritional and Anti–Nutritional Evaluation of Garri Processed by Traditional and Instant Mechanical
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Original Research Article Nutritional and Anti–Nutritional Evaluation of Garri Processed by Traditional and Instant Mechanical Methods ABSTRACT Aim : The aim of this study is to evaluate the nutritional and anti-nutritional composition of garri processed by traditional and instant mechanical methods. Place and Duration of Study : This study was carried out in Achara, Uturu and analyses were done at the Biochemistry and Central Laboratories of Gregory University, Uturu, Abia State between March and July, 2017. Methods : Cassava was harvested and processed in Achara area of Uturu, Abia State. For garri processed by instant mechanical method, cassava was grated and dewatered using hydraulic press and were roasted (fried) within 24 hours of harvest. For garri processed by traditional method, the grated garri was allowed to stay for 24 hours in the sack before dewatering using sticks. The dewatering process took 3 days before roasting. The nutritional and anti-nutritional composition of raw cassava mash, garri processed by traditional and instant mechanical methods were evaluated using standard methods. Results : The result of the analysis showed that garri processed by traditional method was higher in most of the nutritional factors but lower in all of the anti-nutritional factors investigated when compared with those of garri processed by instant mechanical method and raw cassava mash. Garri processed by traditional method was significantly higher in vitamin A but lower in vitamin C when compared with garri processed by instant mechanical method at p<0.05. Garri with palm oil has its cyanogenic glucoside significantly reduced when compared with garri without palm oil at p<0.05. Conclusion : Long period of fermentation (3 – 5 days) of cassava product is recommended as garri processed by traditional method was nutritionally better than that processed by instant mechanical method due to the longer period of fermentation. Keywords : Nutritional content, Anti-nutritional content, Garri processed by Traditional method, garri processed by instant mechanical method, fermentation period 1. INTRODUCTION carbohydrates in the tropics, after rice and maize. It is a major staple food in the developing Cassava ( Manihot esculenta Cranz) is a woody world, providing a basic diet for over half a billion shrub native to South America of the spurge people [3] . It is one of the most drought-tolerant family, Euphorbiaceae [1]. It is extensively crops, capable of growing on marginal soils. In cultivated as an annual crop in tropical and 2014, global production of cassava root was 268 subtropical regions for its edible starchy million tonnes, with Nigeria as the world's largest tuberous root, a major source of carbohydrates producer of nearly 55 million tonnes or 21% of [2]. Cassava is the third largest source of food the world total [4]. Cassava is classified as either sweet ( Manihot Abia State, Nigeria. More recently, it was also palmata ) or bitter ( Manihot esculenta or Manihot reported in the national dailies on Tuesday 1 st utilissima ). Like other roots and tubers, both November, 2016 that six persons (including a bitter and sweet varieties of cassava contain mother, her three children and her two anti-nutritional factors and toxins, with the bitter neighbours) died after consumption of cassava varieties containing much larger amounts [5] . It product (‘lafun’) in Ogaminana area of Okene in must be properly prepared before consumption, Kogi State, Nigeria [11]. as improper preparation of cassava can leave enough residual cyanide to cause acute cyanide Fermentation is an important processing intoxication, goiters, and even ataxia, partial technique for cassava, especially in Africa. paralysis, or death [6]. The more toxic varieties Three major types of fermentation of cassava of cassava are a fall-back resource (a "food roots are recognized: the grated root security crop") in times of famine or food fermentation, fermentation of roots under water insecurity in some places. Farmers often prefer and mould fermentation of roots in heaps [12]. the bitter varieties because they deter pests, The grated cassava roots are allowed to ferment animals, and thieves [7]. in sacks for 3-7 days, which encourages lactic acid fermentation. The pH after 3 days In Nigeria, as in most African countries, cassava decreases from 6 to 4 and the fermentation is is one of the most important carbohydrate dominated by lactic acid bacteria [5]. Grating is sources. About 95 percent of cassava is important for bringing linamarin into contact with consumed as food and less than 5 percent of it linamarase allowing its hydrolysis to glucose and is used for industrial purposes [8]. It is usually cyanohydrin and then to HCN [13]. The consumed in processed forms. In recent times, hydrolysis continues during the fermentation several processing options have emerged from process. Lactic acid fermented products are cassava such as garri, fufu, starch, flour, tapioca reported to have significant concentrations of and chips. Irrespective of these options, garri cyanohydrins because pH decreases during (roasted granules) and edible starch (which is a fermentation and cyanohydrin is stable at low by-product from drying the grated tubers) have pH. The processes of garri production reduce maintained an important position in the food cyanogen contents by more than 95 % [12]. timetable of many households in Nigeria and Fermentation of cassava roots under water, other countries of the world, although starch followed by sun drying, is reported to be the best consumption is most notable in the south-south for cyanogens removal [14]. This type of region of Nigeria [9]. fermentation is used more in areas where there is a sufficient supply of water such as near a Toxicity of cyanide in cassava products has river or lake, and is common in countries such been reported. There are as well few reported as Nigeria, Democratic Republic of Congo, cases of death linked to consumption of cassava Tanzania and Malawi [12]. Heap fermented meals [10]. The incidents of cassava toxicity cassava root products are produced in Tanzania parallel severe hunger condition associated with [15], Uganda and Mozambique [16]. The drought or wartime when processors adopt process involves peeling of cassava roots, sun “shortcut” (shortened process time) in order to drying for 1 to 3 days, heaping and covering, meet market demand. Consumption of garri has fermentation, scraping off the molds, crushing always been a trend in Nigeria and some other into crumbs, sun drying, pounding and sieving parts of the world. The consumption of this into flour. During the fermentation of the roots, product has been accompanied with some side the temperature inside the heaps increases effects like food poisoning and other related between 23 and 29 ℃ higher than the effects due to inefficiency in the course of temperature outside the heaps (2 to 12 ℃). production, which inevitably leads to improperly According to Sani and Farahni, [16], heap processed product, and when this product is fermentation is dominated by the Neurospora consumed, it results to food poisoning and its sitophila, Geotrichum candidum and Rhizopus effect can be fatal [10]. oryzae. Heap fermentation of cassava roots followed by sun drying is capable of reducing the On 20 th March 1994, one Mrs. Loveth Osueke cyanogen levels by 95 % [16]. was reported in the National dailies to have died after eating African Salad made from cassava 2. MATERIALS AND METHODS which she bought from Ariaria market in Aba, 2.1. Production of Garri 24 hours of harvest. For garri processed by traditional method, the grated cassava mash Cassava was harvested and processed in was allowed to stay for 24 hours in the sack Achara area of Uturu, Abia State. For garri before dewatering using sticks. The dewatering processed by instant mechanical method, process took 3 days before roasting. The two cassava was grated and dewatered using methods of processing were as described by hydraulic press and were roasted (fried) within Olukosi et al ., [17]. Fresh Cassava tubers Peeling off the cortex Washing Grating Bagging Dewatering with hydraulic press for few hours Sieving Roasting (with or without addition of palm oil) Garri Figure 1: Stages of processing Garri by Instant Mechanical Method Fresh Cassava tubers Peeling off the cortex Washing Grating Bagging Dewatering with sticks for 3 – 5 days, fermentation takes place Sieving Roasting (with or without addition of palm oil) Garri Figure 2: Stages of processing garri by traditional method 2.2 Determination of Parameters 2.3 Statistical Analysis Nutritional and anti-nutritional analyses of raw Data were subjected to analysis of variance cassava mash, garri processed by instant using the Statistical Package for Social Sciences mechanical method and garri processed by (SPSS), version 20.0. Results were presented traditional were carried out according to the as Mean ± Standard Error of the mean (SEM). methods described by AOAC [18]. Vitamin A 2–tailed t–test was used for comparison of the content was determined as beta-carotene means. Differences between means was spectrophotometrically using the low volume considered to be significant at p<0.05. hexane extraction method described by Fish et al . [19] while the vitamin C content was determined using the method of Benderitter et al . [20]. 3. RESULTS AND DISCUSSION Table 1: Proximate Composition of Garri Samples (%) Parameters Raw Cassava Mash Instant Mechanical Garri Traditional Garri Moisture 6.16 ±0.21 a 4.04 ±0.06 b 4.22 ±0.12 b Crude Fibre 3.81 ±0.25 a 2.35 ±0.02 b 2.77 ±0.05 b Ash 2.00 ±0.10 a 1.91 ±0.12 ab 1.78 ±0.13 b Crude Fat 2.27 ±0.05 a 3.86 ±0.02 b 4.69 ±0.04 c Crude Protein 2.14 ±0.06 a 3.93 ±0.02 b 5.08 ±0.15 c Carbohydrate 83.64 ±2.90 a 83.92 ±1.63 a 81.43 ±1.97 a Values are presented as Mean ±S.E.M, n =3.