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Berries rich in anthocyanins have beneficial effects on postprandial glycaemia. We investigated whether blackcurrant (75 g in a portion) independently and in a product with fermented quinoa induced similar effects on the sugar-induced postprandial glucose metabolism as observed before with 150 g of blackcurrant. Twenty-six healthy subjects (twenty-two females and four males) consumed four test products after fasting overnight in a randomised, controlled crossover design. Each test product portion contained 31 g of available carbohydrates and had similar composition of sugar components: 300 ml water with sucrose, glucose and fructose (SW; reference), blackcurrant purée with added sugars (BC), a product consisting of the blackcurrant purée and a product base with fermented quinoa (BCP) and the product base without blackcurrant (PB). Blood samples were collected at 0, 15, 30, 45, 60, 90, 120 and 180 min after eating each test product to analyse the concentrations of glucose, insulin and NEFA. In comparison with the SW, the intake of both the BC and BCP resulted in reduced glucose and insulin concentrations during the first 30 min, a more balanced decline during the first hour and improved glycaemic profile. The BCP induced more efficient effects than the BC due to the product base with fermented quinoa. A rebound of NEFA after the sugar-induced hypoglycaemic response was attenuated at the late postprandial phase by the BC and BCP. In conclusion, we showed that 75 g of blackcurrant and the product with fermented quinoa were able to lower postprandial glycaemia and insulinaemia.

Dietary fiber is a nutritional concept based not on physiological functions but on defined chemical and physical properties. Recent definitions of dietary fiber differentiate inherent plant cell wall-associated fiber from isolated or synthetic fiber. For the latter to be defined as fiber, beneficial physiological effects should be demonstrated, such as laxative effects, fermentability, attenuation of blood cholesterol levels, or postprandial glucose response. Grain fibers are a major natural source of dietary fiber worldwide, while inulin, a soluble indigestible fructose polymer isolated from chicory, and polydextrose, a synthetic indigestible glucose polymer, have more simple structures. Inulin and polydextrose show many of the same functionalities of grain fiber in the large intestine, in that they are fermentable, bifidogenic, and laxative. The reported effects on postprandial blood glucose and fasting cholesterol levels have been modest, but grain fibers also show variable effects. New biomarkers are needed to link the physiological functions of specific fibers with long-term health benefits.

Intake of wholegrain foods, as well as foods with slow glycemic response, is associated with reduced risk of chronic diseases. Since glycemic responses to breads made of wholemeal flour are high, retarding the glycemic response of a wholemeal bread would further increase its health benefits. The aim was to study postprandial glucose and insulin responses of wholemeal wheat breads in relation to baking technology. Breads were baked using 100% flour from peeled (2%) wheat kernels by straight dough or sourdough fermentation method, and with or without addition of xylanase during mixing of dough. Standard white wheat bread was used as reference. Eleven subjects with insulin resistance and features of the metabolic syndrome were served the breads in random order. Each test bread portion contained 50g of available carbohydrate. Blood samples for measuring glucose and insulin concentrations were drawn at eight time points over four hours. Nutrient composition and the content of soluble protein of the test breads were determined. In vitro hydrolysis of protein and molecular weight of the protein hydrolysates were also performed. The wheat bread produced using sourdough fermentation had the lowest postprandial glucose and insulin responses. Plasma glucose concentration was lower at time points 45, 60, 90 and 120 min (p