BIOCHEMICAL COMPOSITION AND NUTRITIONAL EVALUATION OF BARLEY RIHANE (HORDEUM VULGARE L.).

BACKGROUND: Many experimental studies have suggested an important role for barley Rihane(BR)in the prevention of colon cancer and cardiovascular diseases. The objective of this study was to evaluate the physico-chemical properties and nutritional characterizations of BR compared to other varieties grown in Tunisia (Manel, Roho and Tej). MATERIAL AND METHODS: Total, insoluble and soluble dietary fiber(ß-glucan), total protein, ash and some minerals of BR and Tunisian barley varieties were determined. RESULTS: The results revealed that BR is good source of dietary fiber mainly ß-glucan compared to the other varieties. This variety is a relatively rich source of phosphorous and potassium and it contains many important unsaturated fatty acids. BR has higher nutritional value than other varieties. CONCLUSION: Barley Rihane has significant nutritional characterizations compared to others Tunisian barleys varieties. Abbreviations: BR, Barley Rihane; LDL, low density lipoprotein; HDL, high density lipoprotein; AOM, azoxymethane; TBV, Tunisian barley varieties; TGW, thousand grain weight; SW, weight specific; TDF, total dietary fiber; IDF, insoluble dietary fiber; SDF, soluble dietary fiber; DM, Dry Matter.

Phytochemical content and antioxidant properties of diverse varieties of whole barley (Hordeum vulgare L.) grown in Tunisia.

Four varieties (Rihane, Manel, Roho, and Tej) of Tunisian barley were analysed for their antioxidant activities (AA) using ABTS and DPPH radicals cation, and ferric reducing/antioxidant power (FRAP) methods. The total phenolic (TPC), total flavonoid (TFC) and condensed tannins (CTC) contents were measured. The results indicated that the total phenolic contents ranged from 195.02 ± 0.32 to 220.11 ± 0.32 mg gallic acid equivalent/100g fresh weight. Results showed that Rihane has the highest TPC, TFC and CTC compared to other varieties. Roho barley had a lower activity than Tej barley. A significant correlation (p<0.05) was found between TPC, TFC, CTC and AA. This study suggests that Tunisian barley varieties may serve as a good source of natural antioxidants.

Effect of dietary fibre of barley variety 'Rihane' on azoxymethane-induced aberrant crypt foci development and on colonic microbiota diversity in rats.

Many epidemiological and experimental studies have suggested an important role for dietary fibre (DF) of cereals in the prevention of colon cancer. The objective of the present study was to explain the effects of the DF of barley Rihane (BR) on azoxymethane (AOM)-induced aberrant crypt foci (ACF) and colonic bacterial diversity in rats. Following an acclimatisation period, rats were divided into four groups and fed a control (C) diet or experimental diet containing 30 % of BR. DF content in the experimental diet was twice that of the C diet (total DF was 8·69 % in the C diet and 15·24 % in the BR diet). At 7 and 8 weeks of age, rats received two successive subcutaneous injections of AOM at 20 mg/kg body weight. At 12 weeks after the first injection, ten animals from each group were killed. The BR diet decreased colonic pH (P < 0·05) compared with the C diet. The total number of ACF observed decreased considerably in the BR/AOM group compared with the C/AOM group (P < 0·05). Comparison of similarity coefficients showed variability of colonic microbiota species between the different groups. In addition, we showed inter-individual variability within the same group. This similarity was affected by BR and AOM. The present results show that bifidobacteria numbers were lower in rats fed the BR diet compared with those fed the C diet. However, the number of enterobacteria in colonic content was increased (P < 0·05) in the BR group compared with the C group. The results from the present study show that the DF of BR reduced the incidence of AOM-induced ACF and increased microbiota biodiversity.