Physicochemical and nutritional properties of twenty three traditional rice (Oryza sativa L.) varieties of Sri Lanka

Objective: To evaluate the physicochemical and nutritional properties of selected traditional rice varieties of Sri Lanka. Methods: Twenty three rice varieties were selected. All the varieties were studied for grain colour, grain size and shape as physicochemical properties, while for nutritional properties, moisture, crude ash, crude protein, crude fat and total carbohydrate contents were studied. Only selected set of varieties were studied for total, soluble and insoluble dietary fiber. These properties were studied using internationally accepted standard techniques. Results: The results showed significant (P < 0.05) difference in the physicochemical and nutritional properties of the studied varieties. Out of 23 varieties tested, 20 varieties were red rices, while the rest were white rices. The grain size and shape were mostly medium bold (30%) and short bold (56%). The mean moisture, crude ash, crude protein, crude fat and total carbohydrate contents of selected varieties varied from (10.42 ± 0.25)% to (12.33 ± 0.02)%, (1.30 ± 0.14)% to (1.92 ± 0.05)%, (10.59 ± 0.12)% to (13.27 ± 0.32)%, (2.18 ± 0.10)% to (4.12 ± 0.28)% and (81.42 ± 0.25)% to (85.66 ± 0.24)%, respectively. The selected varieties had total, soluble and insoluble dietary fiber contents in the range of 4.2%–6.9%, 0.8%–2.1%and 3.1%–4.8%, respectively. The varieties Pachchaperumal, Suduru samba, Wanni Dahanala, Gonabaru and Sudu Heeneti had the highest crude protein, crude fat, crude ash, total carbohydrate and dietary fiber contents, respectively. Conclusions: Selected traditional rice varieties of Sri Lanka had physicochemical properties preferred by consumers and nutritional properties with dietary importance.

Anti-diabetic related health food properties of traditional rice(Oryza sativa L.)in Sri Lanka

Objective:To evaluate a range of anti-diabetic related properties and some consumer preferred physicochemical properties of selected Sri Lankan traditional rice varieties.Methods:Sudu Heeneti,Goda Heeneti,Masuran and Dik Wee varieties were used in this study.Anti-diabetic related properties of bran extracts of selected varieties were studied for methylglyoxal mediated protein glycation inhibition,acetyl and butyryl-cholinesterase inhibition in vitro and anti-hyperglycemic activity in vivo.Further,selected varieties were studied for starch hydrolysis rate in vitro.Physicochemical properties including grain color,size,shape,crude protein,crude fat,ash,dietary fiber and total carbohydrate contents were studied.Results:Brans of selected varieties had significant(P<0.05)and dose dependent methylglyoxal mediated protein glycation inhibition[IC_(50):(174.77±6.65)to(342.87±0.43)μg/mL]and acetyl[IC_(50):(37.00±0.68)to(291.00±3.54)μg/mL]and butyryl-cholinesterase[IC_(50):(18.50±0.60)to(96.60±0.56)μg/mL]inhibitory activities.Further,Sudu Heeneti,Masuran and Dik Wee had low starch digestion rate(52.40±1.44 to 53.76±1.19)indicating that these varieties may be low glycemic index rices.Brans of Masuran tested in rat model showed anti-hyperglycemic activity.Physicochemical properties studied showed that selected varieties were red in color and grain size and shape were mostly medium and bold respectively.Moisture,crude protein,crude fat,ash and total carbohydrate contents varied significantly(P<0.05)among the varieties.Conclusions:It is concluded that selected varieties could be promoted as physicochemically sound rices with a range of anti-diabetic related properties in the management of diabetes and its complications.

Antioxidant potential of brans of twenty-nine red and white rice (Oryza sativa L.) varieties of Sri Lanka

Objective: To evaluate antioxidant properties of brans of twenty-nine red and white rice varieties of Sri Lanka. Methods: Brans of 21 new improved (NI), 2 old improved (OI) and 6 traditional red and white rice varieties of Sri Lanka were studied for range of antioxidant properties. The studied antioxidant properties included total polyphenolic content (TPC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging activity in vitro. Bran of black rice variety from Korea was also studied for the same antioxidant properties for comparison. Results: Results exhibited significantly high ABTS and DPPH radical scavenging activities and 10, 7 and 2.5 fold greater TPC, FRAP and ORAC activities in brans of red rices (BRRs) compared to brans of white rices irrespective of NI, OI and traditional rice types. Among BRRs traditional varieties had greater ABTS and DPPH radical scavenging activities and 1.7, 1.3 and 1.2 fold respectively greater TPC, FRAP and ORAC in contrast to NI red rices. Traditional red rice varieties, Kalu Heeneti (TPC and ORAC), Pachchaperumal (TPC and DPPH) and Kurulu Thuda (DPPH) and OI red rice variety H4 (FRAP) exhibited the highest activities for the antioxidant properties studied. Further, these varieties had significantly high activities compared to black rice. Conclusions: In conclusion, BRRs especially traditional red rices had greater antioxidant properties and consumption may be useful in managing various chronic diseases.

In vitro pancreatic lipase,cholesterol esterase and cholesterol micellization inhibitory activity of Sri Lankan low grown orthodox Orange Pekoe grade black tea(Camellia sinensis L.)

Objective:To access the pancreatic lipase,cholesterol esterase and cholesterol micellization inhibitory activities of Sri Lankan low grown orthodox Orange Pekoe grade black tea made from uppermost tender leaves and unopened buds of Camellia sinensis L.Methods:Black tea brew(BTB)was made according to International Organization for Standardization 3103 specifications and concentrations of BTB tested were 37.5,75.0,150.0,300.0 and 600.0μg/mL for antilipase and anti-cholesterol esterase assays and 0.25,0.50 and 1.00μg/mL for cholesterol micellization inhibitory assay.Results:The results showed that BTB of Sri Lankan low grown orthodox Orange Pekoe grade black tea has marked and dose-dependent(r^(2)=0.95)cholesterol micellization inhibitory activity in vitro comparable to epigallocatechin gallate,the reference drug used.In contrast,BTB had only mild but dose-dependent(r^(2)=0.94)inhibitory activity against pancreatic lipase and weak inhibitory effect(up to 13.17%)on pancreatic cholesterol esterase.Conclusions:It is concluded that consumption of BTB of Sri Lankan low grown orthodox Orange Pekoe grade tea as a beverage may be a useful strategy in the management of hyperlipidaemia.

Sri Lankan black tea(Camellia sinensis L.)inhibits the methylglyoxal mediated protein glycation and potentiates its reversing activity in vitro

Objective:To evaluate inhibitory activity of methylglyoxal(MGO)mediated protein glycation and ability to potentiate its reversing activity and range of antioxidant properties of Sri Lankan low grown orthodox orange pekoe grade black tea.Methods:Freeze dried black tea brew(BTB)was used as the sample in this study.Antiglycation and glycation reversing activity was studied in bovine serum albumin(BSA)-MGO model.Antioxidant properties were studied using total polyphenolic content,total flavonoid content,2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid,1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power in vitro antioxidant assays.Results:The results demonstrated significant(P<0.05)and dose dependant inhibition of BSA-MGO glycation[IC_(50):(164.30±4.85)μg/mL],potentiating of its reversing activity[EC_(50):(235.39±5.37)μg/mL]and marked antioxidant properties[total polyphenolic content:(119.55±9.97)mg gallic acid equivalents/g BTB;total flavonoid content:(6.04±1.26)mg quercetin equivalents/g BTB;2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid,1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power:(3.29±0.06),(1.95±0.15)and(1.31±0.19)mmol Trolox equivalents/g BTB,respectively].No correlations were observed between antioxidant activity and BSA-MGO glycation.Conclusions:The novel properties observed for Sri Lankan orange pekoe grade black tea indicate its usefulness as a supplementary beverage in managing MGO and advanced glycation end products related diseases and ailments.