Proceedings of National Symposium - Faculty of Agriculture

Cover page

2009-09-10T00:00:00Z

Cover page

Preliminary Pages

2009-09-10T00:00:00Z

Preliminary Pages

Evaluation of Functional Properties of Some Traditional and Improved Rice Varieties with Special Reference to Glycemic Index

2009-09-10T00:00:00Z

Evaluation of Functional Properties of Some Traditional and Improved Rice Varieties with Special Reference to Glycemic Index Fernando, G.S.N.; Herath, H.M.T.; Wijeratne, V. Rice is the staple food of Sri Lanka and can be used effectively to increase the health status of our community. Diabetes is one of the major health issues facing Sri Lankans today. Glycemic Index can be defined as the blood glucose response of a particular food compared to a standard and, moreover, it is important for diabetic people in planning their diets. As the staple food, it is important to identify the Glycemic Index and related functional properties of available rice varieties to enhance the health status of our community. The objective of the study was tp; determine the amylose content, dietary fiber content and Glycemic Index of selected rice varieties grown in Sri Lanka. Ten rice varieties, both traditional and improved, were used for the study. Amylose content and dietary fiber contents were determined using simple iodine colorimetric method and enzymatic gravimetric method, respectively, for both polished and unpolished rice samples. Proximate composition of ten rice varieties and white bread was determined and the available carbohydrate content was calculated, Glycemic response for eight unpolished rice varieties, four polished rice varieties and white bread was determined using in-vitro digestibility method. Amylose content of unpolished rice varieties ranged from 29.4% (Dik wee) to 25.7% (Sulai) and in polished rice varieties ranged from 29.4% (Bg 359) to 25.9% (Dik wee) having the highest and the lowest values. Dietary fiber contents of unpolished varieties ranged from 4.3% (Sulai) to 2.5% (Bg3-52) and in polished varieties ranged from 3.1% (Kalu heenati) to 0.1% (Kalu heenati) having the highest and lowest values. Glycemic Index of unpolished rice varieties ranged from 108.50% (Bg 359) to 61.81% (Sulai) and in polished varieties ranged from 70.56% (Sulai) to 64 (Rath suwadal) having the highest and lowest values. There was a significant difference (P<0.05) of amylose content among unpolished rice varieties as well as polished Varieties. But, there was no significant difference (P>0.05) in amylose content between polished and unpolished varieties. There was a negative correlation between dietary fiber content and Glycemic Index, but there was no correlation between amylose content and Glycemic Index. Therefore, amylose content alone may not be a good predictor of Glycemic Index and there may be other factors influencing the Glycemic Index of rice. Moreover, particle size of cooked rice and polishing rate appeared to have an impact on Glycemic Index.

Exploring the Possibility of Using Jak Seed Flour (Artocarpus heterophylhis) for Biscuit Manufacture with an Appropriate Flavor Booster

2009-09-10T00:00:00Z

Exploring the Possibility of Using Jak Seed Flour (Artocarpus heterophylhis) for Biscuit Manufacture with an Appropriate Flavor Booster Biscuits are a popular food product among the Sri Lankan consumers and are mainly prepared using wheat flour. Underutilized local raw materials could be made use of in the preparation of biscuits to reduce the wheat flour consumption and to increase the nutritional quality. Jak (Artocarpus heterophyllyus) is a common tree grown in the wild, and is also cultivated. It is used in both its ripe and unripe state. However, during the harvesting season there is usually a glut, leading to wastage and distress sale. Therefore, there is an ample scope for processing the fruit into value-added products. Hence, this study was carried out in exploring the possibility of using Jak seed flour (JF) in biscuit manufacture. Jak seeds (8kg) from well ripen fruits were harvested and 16 treatment combinations with 4 variables (aging process, heat treatment, soaking with NaHC03 and refrigeration) were prepared with respect to the experimental design. Jak seeds obtained from each treatment were dried at 80 °C for 6 h, ground using a laboratory grinder and subjected to measurement of particle size. Jak seed flour obtained from each treatment was used to manufacture biscuits. Two best treatment combinations were selected, and blends of jack seed flour (JF), rice flour (RF) and wheat flour (WF) were prepared for both on a replacement basis (JF/RFAVF, 100:0:0, 90:10:0 and 90:0:10). Biscuits were produced from the blends and selected the best sample by evaluating their sensory properties. Commercial biscuit was used as a control. All sensory evaluation results were analyzed by using Kruskall-Wallis method. An appetite booster was developed using icing sugar and natural, waraka {Artocarpus heterophyllus Lam) extract. Cream was applied in between two biscuits (the best composite biscuit). The best biscuit with filling material was selected using the Duo-trio test and analyzed for its proximate composition just after preparation and after 3 months of storage. Moreover, microbiological examination of samples was carried out after 3-months of preparation. Results revealed that fresh Jak seeds were capable of yielding finer particle than the seeds with aging process. Raw seed without treated and raw seed soaking with NaHC03 were the best in preparing biscuits. JE. WF (90:10) biscuit obtained the highest mean rank for texture, crunchiness, taste, smell, hardness, mouth feel and overall acceptability and it was selected as the best. Contents of ash, moisture, protein, fat, crude fibre and carbohydrates of JF:WF (90:10) biscuits were 3.20%, 3.53%, 10.65%, 14%, 0.37% and 68.25%, respectively. Similar values were observed after 3 months of storage. Responses were clearly identified for the biscuits with waraka flavoured appetite booster. Total Plate Count (TPC) and Yeast and Mould counts of appetite booster were 1.0*104 CFU/g and 6.7x102 CFU/g, respectively and cream was free of Escherichia coil.