The aim of the study is to determine the optimal mixture of sucrose with isomaltulose that will produce optimal reduction in glycaemia and an acceptable sensory profile. These will be assessed among three different ethnicities.The study will recruit a maximum of 60 healthy young (21-60 years old) males from three ethnicities (Malay, Indian, and Chinese). Each participant will take part in 9 separate test sessions on nonconsecutive days, and consume 3 reference control drinks and 6 different test drinks. On each of the test days, participants will consume either the reference drink (50g of anhydrous glucose dissolved in 300 ml of water) or one of the test drinks which consists of 50g of sucrose and/or isomaltulose dissolved in 300 ml of water in the following ratios: 0:100, 100:0, 50:50, 80:20, 70:30, 60:40 sucrose:isomaltulose. Study population: The study will recruit a maximum of 65 healthy young (21-60 years old) males. At least 10 participants will be selected from the three ethnicities (Malay, Indian, and Chinese). Males will be selected in order to avoid effects of the menstrual cycle. Participants will be recruited from the general public in Singapore and will be between 21 and 60 years, with a body mass index between 22 and 27 kg/m2.Design: The experimental protocol adopted is a pre-validated method used repeatedly for measuring the GI of foods. The testing follows a randomised, single-blinded, between-subjects, crossover design with participants returning on 9 non-consecutive days. Reference food testing (standard glucose solution) will precede test food testing. On each test day, participant will consume either the reference drink or one of the test drinks. The test sessions will be made up of 3 identical reference drinks and 6 test drinks. The number sessions each participant will complete will be determined by the researcher and communicated to the participant. For the 9 test sessions, participants arrive at the laboratory between 8:30-9 am following a 10 hour overnight fast. They are instructed not to partake in intense level sports and avoid alcohol consumption on the evening prior to a test session. Following a 10 minute rest two blood samples are obtained five minutes apart for determining baseline blood glucose levels. They are then given either the standard or test drink to consume. They are instructed to consume the food at a comfortable pace within 12 minutes. After consumption of the test drink, subjects will complete a liking questionnaire. Further blood samples are obtained at 15, 30, 45, 60, 90, 120, 150 and 180 minutes for blood glucose measurements and insulin (at every half hour intervals).Reference/Test foods: The reference drink will be anhydrous glucose (50 g) (standard) dissolved in 300 ml of water) and will be consumed on 3 occasions. The test drinks will consist of 50g of sucrose and/or isomaltulose dissolved in 300 ml of water in the following ratios: 0:100, 100:0, 50:50, 80:20, 70:30, 60:40 sucrose:isomaltulose. A total of 6 test drinks will be tested. The participant will be requested to finish both reference and test drink within 12min.Blood collection: Participants will be asked to attend the testing sessions after an overnight fast of ten to twelve hours. Two fasting blood samples will be collected by finger prick for glucose measurement and not more than 0.5ml finger prick blood sample will also be collected to measure baseline insulin. A drop of blood will be collected into a HemoCue® cuvette (Helsingborg, Sweden) for blood glucose analysis. In addition, not more than 0.5ml of finger prick blood will be collected for the analyses of plasma insulin concentrations. Participants will then consume the test meal within 12 minutes. Following this, approximately 5µl of blood samples will be collected at 15, 30, 45, 60, 90, 120, 150 and 180min for glucose measurements and not more than 0.5ml of blood samples will be collected at 30, 60, 90, 120, 150 and 180min for insulin measurements.'Liking' questionnaire: On the testing session days, participants will be asked to rate their 'liking' for the test meal. Participants will be rate their 'overall liking' for the test meal on a 100 mm Visual Analog Scale anchored with 'dislike extremely' (0 mm), 'neither like nor dislike' (50 mm) and 'like extremely' (100 mm) immediately after they consume the test meal.Screening: Potential participants will first attend a screening session for consenting and eligibility procedures. Participants will arrive in the morning following an overnight fast. During the screening, a questionnaire will have to be completed and anthropometry and blood pressure will be assessed. Screening questionnaire: The screening questionnaire will include contact information, demographic, general health details, and physical activity level. This information will be used to determine whether the participant is eligible for the study, as well as to check for any possible confounders that may influence the study outcomes. Anthropometric measurements: Body weight and body composition will be measured using bioelectrical impedance analysis. Height will be measured using a stadiometer in order to calculate participants' BMI. Waist circumference will be measured at the minimum circumference between the iliac crest and the rib cage. Hip circumference will be measured at the maximum protuberance of the buttocks. Blood pressure will also be measured. Blood pressure: Blood pressure will be measured using an Omron blood pressure monitor (Model HEM-907) at baseline. Participants will be seated for five minutes before blood pressure is measured. Measurements will be taken in duplicate and the averaged results will be recorded.
