Gari Samples Research Articles

Physicochemical properties and garification (gari yield) of selected cassava cultivars in Rivers State, Nigeria.

Gari was processed from six different cassava cultivars TMS 3575, TMS 3044, hormone treated variety (HTV), TMS 30555, TMS 40944 and TMS 30572. Chemical analyses of the gari samples showed pH values of: 4.0, 4.0, 3.9, 3.6, 3.4, 3.6 and total titratable acidity of 0.99, 0.99, 0.98, 0.85, 0.96, 0.85 (% lactic acid) for TMS 3575, 3044, HTV, 30555, 30572, and 40944 respectively. Physical characteristics of the samples showed the swelling index of 264.5%, 223.5%, 364.0%, 321.3%, 241.3% and 232.7%, water absorption capacity of 1.0 ml/g, 0.8, 1.5, 1.9, 1.7, 1.9 ml g(-l) sample, relative bulk density of 0.29, 0.30, 0.15, 0.17, 0.15 (g/cm3) and gari yield of 34%, 21%, 33%, 24%, and 23%, for cultivars, TMS 3575 (2), 3044, HTV, 30555, 30572, 40944 respectively. Sensory evaluation showed a significant difference (p < 0.05) in quality and overall acceptability among the samples while Tukey test showed a difference (p<0.05) between HTV and between 3575 and 3044. The cassava pulp from the cultivars and their corresponding gari had HCN content (mg/100 g) ranging from 7.9 to 9.3 for pulp and 1.1 to 1.5 for gari, respectively. The 72 hours fermentation period reduced the HCN in all cultivars by 85%, which is considered to be a safe level for human consumption.

Thiocyanate levels of mainly dietary origin in serum and urine from a human population sample in Port Harcourt, Nigeria.

Thiocyanate levels were determined in serum and urine samples obtained from a human population sample of healthy non-smoking volunteers (aged between 14 and 30 years) of both sexes known to eat gari-based meals at least once a day. The samples were collected before and 3-4 hours after a gari- or rice-based meal. The values obtained before the test meals showed a wide variation, ranging between 39.20 +/- 1.95 to 160.95 +/- 8.06 mumol/l of serum, and 81.92 +/- 9.78 to 294.01 +/- 14.70 mumol/l of urine. For each volunteer, the serum and urine thiocyanate were affected by the test meals. Average increases of 18 and 20% were observed for serum and urine thiocyanate, respectively, following a gari-based meal. A rice-based meal produced, on the average, 10% decrease in both serum and urine thiocyanate. No significant effect of sex or age on the thiocyanate levels was observed. The gari samples used in the study, as well as random samples from the locality of study, had no detectable thiocyanate but contained between 0.013 and 0.015 mg cyanide per kg of gari. These findings indicate that conversion to thiocyanate is a significant pathway in the metabolism of HCN and contributes significantly to thiocyanate found in body fluids and tissues of man. In addition, support is provided for the possible involvement of the sulphur-transferases in the process of cyanide detoxication.

Quality of cassava foods in Sierra Leone

AbstractGari and foofoo (fermented cassava foods) were purchased in the Freetown markets of Sierra Leone and analysed for factors associated with quality. Sellers were generally knowledgable about the source of the products which all originated from the country areas outside Freetown. The mean cyanide contents were higher (8.6 mg kg−1 DM for gari and 28.2 mg kg−1 DM for foofoo) than the amounts suggested by the Codex specification and, because of the distribution of the values around the mean, some samples necessarily contained unacceptable amounts of cyanide. Cyanogens were present as the cyanohydrin or as free cyanide; no glucoside was detected. Microbiological analysis of the samples showed high counts for total organisms, fungi and Enterobacteriaceae (106–107 g−1). The mean water content of gari was 119 g kg−1 which falls within the recommended limit of 120 g kg−1 but again, due to the distribution of values around the mean, some samples had considerably higher water contents than that limit. Titratable acidity and pH were measured and the mean pH values were 4.18 for foofoo and 4.55 for gari. The particle size and swelling power of gari samples were also measured as these relate to consumer acceptance. The data show the quality of current cassava foods marketed in a major urban centre in Sierra Leone. As centralised processing develops, improvements can be made to those quality parameters which have been identified as important.

The mycoflora of gari

Mycological studies have been carried out on market samples of gari, a ready‐to‐use staple fermentation product of cassava (Manihot esculenta cranz). Commercial and industrial samples were analysed. The moisture contents of samples varied from 7% to 17% while the water activity (aw) varied from 0·52 to 0·85 and the pH of samples ranged from 3·9 to 7·26. Several fungi were isolated from the commercial samples while the industrial packaged samples were relatively mould‐free. Moulds isolated were mainly Aspergillus spp., Penicillium spp., and several Mucorales, e.g. Rhizopus sp., Syncephalastrum sp., Mucor sp. and Circinella sp.

Post-processing microflora and the shelf stability of gari marketed in Port Harcourt.

Gari was examined for its post-processing microbial content. Aerobic mesophilic bacteria and fungi were isolated from all samples. The total viable bacterial counts ranged from 2.0 X 10(2) to 8.0 X 10(4) cfu/g. Fungal counts ranged from 1.0 X 10(2) to 1.5 X 10(4) cfu/g. The total viable counts of fresh samples were much lower than those of market and packaged samples. Bacillus, Micrococcus and Proteus spp. were the bacteria isolated, Aspergillus niger, Aspergillus flavus and Penicillium spp. the fungi. Food borne parasites and pathogens such as Staph. aureus and Clostridium perfringens were not found. The gari samples were quite stable, having a shelf life of 3-6 months. The water activities of the samples ranged from 0.52 to 0.68. Based on the microbial counts of the samples, the critical upper limit for the safety of gari was set at 10(4) cfu/g dry sample.

Effects of processing factors on the quality of gari produced by a steam gelatinization technique

The effects of dice size, fermentation time, blanching time and drying temperature on the total cyanide content and swelling capacity of gari samples produced by the steam gelatinization technique were analysed. The results show that gari produced from 1 cm cubes of cassava roots, fermented for 3 days, blanched for 10 minutes and dried at 55°C had a total cyanide content lower than those of gari produced by the conventional technique. The swelling capacity was also better.

Preliminary studies of a new technique of cassava mash gelatinization

A technique using steam for gelatinizing fermented cassava mash was investigated. The mash which was dewatered to about 50% moisture content (wet basis) was heated to between 88°C and 94°C by steaming. The steamed product when dried had characteristics which compared favourably with five samples of gari produced by conventional techniques. The technique could provide the basis for an alternative technology for gelatinizing fermented cassava mash for gari production.

Cyanide content of gari

500 random samples of gari (a cassava by-product) being hawked for sale in Ibadan markets, in Nigeria, were assayed for hydrocyanic acid (HCN) content. Most of the samples contained detectable amounts of HCN, ranging between 0.8 and 38 mg/kg, and only a very small proportion (0.4%) contained no cyanide. The limit of HCN detection was 0.1 ppm. There was no significant difference ( P < 0.01) between the mean total cyanide (glycoside-bound plus non-glycosidic) and free cyanide (non-glycosidic) contents, 8.0 ± 6.9 mg HCN/kg and 7.2 ± 5.8 mg HCN/kg, respectively; indicating that an overwhelming proportion of the residual cyanide content of commercial gari could be present in the “free” form. The toxicity implications of free cyanide in cassava diets is briefly discussed.