Glycemic response and glycemic index of semolina spaghetti enriched with barley β-glucan

Acute Effects of Dietary Fiber in Starchy Foods on Glycemic and Insulinemic Responses: A Systematic Review of Randomized Controlled Crossover Trials

Dietary fiber (DF) consumption has been associated with improved glycemic control in epidemiological and long-term interventional studies. However, its acute effects are not yet clear. This systematic review aims to elucidate the postprandial effects of DF in starchy products on glycemia and insulinemia. An electronic search of databases was conducted, and forty-one records met the inclusion criteria and underwent a risk-of-bias assessment. It was shown that soluble DF does not clearly affect glycemia in individuals with normal weight, while resistant starch may be more effective in flattening glycemic responses. Concerning insulinemia, both soluble DF and resistant starch have mixed results, with either favorable or no effects. Data on insoluble DF and glucose metabolism are scarce. The same mixed results for glycemia can be seen in healthy volunteers with overweight/obesity, while resistant starch seems to improve insulinemic responses. Finally, more studies need to examine the acute effects of DF in starchy foods on glucose metabolism and insulin secretion in individuals facing glucose abnormalities. Additionally, more studies are needed to prove whether ingesting high-fiber carbohydrate-containing products per se can result in blunted glycemic and insulinemic responses and which DF type and amount are more effective.

Improved Glycemic Control and Variability: Application of Healthy Ingredients in Asian Staples

A reduction in carbohydrate intake and low-carbohydrate diets are often advocated to prevent and manage diabetes. However, limiting or eliminating carbohydrates may not be a long-term sustainable and maintainable approach for everyone. Alternatively, diet strategies to modulate glycemia can focus on the glycemic index (GI) of foods and glycemic load (GL) of meals. To assess the effect of a reduction in glycemic load of a 24 h diet by incorporating innovative functional ingredients (β-glucan, isomaltulose) and alternative low GI Asian staples (noodles, rice)on glycemic control and variability, twelve Chinese men (Age: 27.0 ± 5.1 years; BMI:21.6 ± 1.8kg/m²) followed two isocaloric, typically Asian, 24h diets with either a reduced glycemic load (LGL) or high glycemic load (HGL) in a randomized, single-blind, controlled, cross-over design. Test meals included breakfast, lunch, snack and dinner and the daily GL was reduced by 37% in the LGL diet. Continuous glucose monitoring provided 24 h glycemic excursion and variability parameters: incremental area under the curve (iAUC), max glucose concentration (Max), max glucose range, glucose standard deviation (SD), and mean amplitude of glycemic excursion (MAGE), time in range (TIR). Over 24h, the LGL diet resulted in a decrease in glucose Max (8.12 vs. 6.90 mmol/L; p = 0.0024), glucose range (3.78 vs. 2.21 mmol/L; p = 0.0005), glucose SD (0.78 vs. 0.43 mmol/L; p = 0.0002), mean amplitude of glycemic excursion (2.109 vs. 1.008; p < 0.0001), and increase in 4.5-6.5mmol/L TIR (82.2 vs. 94.6%; p = 0.009), compared to the HGL diet. The glucose iAUC, MAX, range and SD improved during the 2 h post-prandial window of each LGL meal, and this effect was more pronounced later in the day. The current results validate the dietary strategy of incorporating innovative functional ingredients (β-glucan, isomaltulose) and replacing Asian staples with alternative low GI carbohydrate sources to reduce daily glycemic load to improve glycemic control and variability as a viable alternative to the reduction in carbohydrate intake alone. These observations provide substantial public health support to encourage the consumption of staples of low GI/GL to reduce glucose levels and glycemic variability. Furthermore, there is growing evidence that the role of chrononutrition, as reported in this paper, requires further examination and should be considered as an important addition to the understanding of glucose homeostasis variation throughout the day.

Impact of functional vegetable ingredients on the technical and nutritional quality of pasta

Pasta is a popular staple food around world. This makes pasta a great vehicle for delivering functional ingredients. This article reviews the popular functional ingredients - cereals, pseudocereal, legumes and vegetables, that are used to enrich pasta. The influence of these functional ingredients, additives and cooking process on pasta's nutritional, technical and sensory properties is summarized. This article focusses on the effects of different forms of these ingredients on the quality of cereal foods. Such as carrot juice pasta has a superior technical quality than carrot flour pasta. As far as can be established there are very few articles examining the effects of different forms of ingredients on pasta. Puree or liquid form raw vegetable materials offfers a better option than conventional powder form to add to semolina to produce functional pasta with superior technical quality and improved nutritional value.

Emerging science on benefits of whole grain oat and barley and their soluble dietary fibers for heart health, glycemic response, and gut microbiota

The aim of this work is to review the major mechanisms by which consumption of whole grain oats and barley, and β-glucans, reduces the risk of coronary heart disease, type 2 diabetes, and other noncommunicable chronic conditions. These effects have been predominantly explained by the role of soluble dietary fibers and smaller bioactive compounds, such as phenolic compounds, in oats and barley. These help to reduce the level of serum low-density lipoprotein cholesterol, decreasing postprandial blood glucose and modulating gut microbiota. In the present review, the role of viscosity development of the intestinal content by β-glucans in these mechanisms is discussed, as well as the impact of processing conditions altering the composition or the physicochemical characteristics of β-glucans.

Development of the Diabetic Kidney Disease Mouse Model Culturing Embryos in α-Minimum Essential Medium In Vitro, and Feeding Barley Diet Attenuated the Pathology

Diabetic kidney disease (DKD) is a critical complication associated with diabetes; however, there are only a few animal models that can be used to explore its pathogenesis. In the present study, we established a mouse model of DKD using a technique based on the Developmental Origins of Health and Disease theory, i.e., by manipulating the embryonic environment, and investigated whether a dietary intervention could ameliorate the model's pathology. Two-cell embryos were cultured in vitro in α-minimum essential medium (MEM; MEM mice) or in standard potassium simplex-optimized medium (KSOM) as controls (KSOM mice) for 48 h, and the embryos were reintroduced into the mothers. The MEM and KSOM mice born were fed a high-fat, high-sugar diet for 58 days after they were 8 weeks old. Subsequently, half of the MEM mice and all KSOM mice were fed a diet containing rice powder (control diet), and the remaining MEM mice were fed a diet containing barley powder (barley diet) for 10 weeks. Glomerulosclerosis and pancreatic exhaustion were observed in MEM mice, but not in control KSOM mice. Renal arteriolar changes, including intimal thickening and increase in the rate of hyalinosis, were more pronounced in MEM mice fed a control diet than in KSOM mice. Immunostaining showed the higher expression of transforming growth factor beta (TGFB) in the proximal/distal renal tubules of MEM mice fed a control diet than in those of KSOM mice. Pathologies, such as glomerulosclerosis, renal arteriolar changes, and higher TGFB expression, were ameliorated by barley diet intake in MEM mice. These findings suggested that the MEM mouse is an effective DKD animal model that shows glomerulosclerosis and renal arteriolar changes, and barley intake can improve these pathologies in MEM mice.

Reducing the glycemic impact of carbohydrates on foods and meals: Strategies for the food industry and consumers with special focus on Asia

Type 2 diabetes is increasingly prevalent in Asia, which can be attributed to a carbohydrate-rich diet, consisting of foods in the form of grains, for example, rice, or a food product made from flours or isolated starch, for example, noodles. Carbohydrates become a health issue when they are digested and absorbed rapidly (high glycemic index), and more so when they are consumed in large quantities (high glycemic load). The principal strategies of glycemic control should thus aim to reduce the amount of carbohydrate available for digestion, reduce the rate of digestion of the food, reduce the rate of glucose absorption, and increase the rate of glucose removal from blood. From a food perspective, the composition and structure of the food can be modified to reduce the amount of carbohydrates or alter starch digestibility and glucose absorption rates via using different food ingredients and processing methods. From a human perspective, eating behavior and food choices surrounding a meal can also affect glycemic response. This review therefore identifies actionable strategies and opportunities across foods and meals that can be considered by food manufacturers or consumers. They are (a) using alternative ingredients, (b) adding functional ingredients, and (c) changing processing methods and parameters for foods, and optimizing (a) eating behavior, (b) preloading or co-ingestion of other macronutrients, and (c) meal sequence and history. The effectiveness of a strategy would depend on consumer acceptance, compatibility of the strategy with an existing food product, and whether it is economically or technologically feasible. A combination of two or more strategies is recommended for greater effectiveness and flexibility.

Effects of Transglutaminase on the Protein Network and In Vitro Starch Digestibility of Asian Wheat Noodles

Wheat noodles are a staple commonly consumed in Asia, but high intakes have been associated with type 2 diabetes due to its rapid starch digestibility. We hypothesised that protein network-binding via transglutaminase (TG) would form a stronger barrier encapsulating the starch granules to limit enzymatic access and digestion. The amount of glucose release decreased significantly with increasing TG concentration, with a reduction of approximately 16% with 2% TG after 120 min of digestion. The slower rate of glucose release during the first 60 min of digestion for 2% compared to 0% TG suggested impeded first stage enzymatic access rather than second stage starch hydrolysis into glucose. Upon increasing the TG concentration, confocal microscopy revealed a denser protein network with increased connectivity, supported by a decrease in protein solubility and gelatinisation enthalpy, and increased firmness and work of shear. Therefore, transglutaminase can potentially be used to reduce starch digestibility in wheat noodles via protein network-binding.

The effects of prebiotic bread containing oat ß-glucan and resistant starch on the glycemic index and glycemic load in healthy individuals

Purpose

The enrichment of bread with non-digestible prebiotic ingredients may exert health-promoting effects and provide healthier food choices for those suffering from metabolic diseases, including obesity and diabetes. The purpose of this study was to investigate the effects of ß-glucan and resistant starch incorporation on the glycemic index (GI) and glycemic load (GL) of white bread.

Design/methodology/approach

Seven different formulations of prebiotic bread were produced using different proportions of ß-glucan (0.8, 1 and 1.2 per cent), resistant starch (5.5, 8 and 10.5 per cent) and the combination of resistant starch and ß-glucan in a ratio of 4:0.5.

Findings

The GI and GL of the prebiotic bread prepared with 1 per cent ß-glucan (w/w) were 55.7 and 7.8, respectively, whereas those of the prebiotic bread prepared with 8 per cent resistant starch (w/w) were 64.8 and 8.42, respectively, with both breads having significantly lower GI and GL values than the control (P < 0.05). It was concluded that the incorporation of 1 per cent ß-glucan may be beneficial in producing prebiotic bread with both low GI and low GL.

Originality/value

Although white bread is a main food source in human diet, its high GI and GL make it an unhealthy food choice. The incorporation of ingredients with prebiotic effects, such as ß-glucan and resistant starch, can improve the nutritional value of this product by lowering its GI and GL.

Glycaemic indices and glycaemic loads of common Korean carbohydrate-rich foods

Glycaemic index (GI) and glycaemic load (GL) values of foods consumed in Asia remain poorly characterised despite the fact that Asian diets are high in carbohydrates. We evaluated the GI and GL of the most commonly consumed carbohydrate-rich foods, according to food type and cooking methods. GI and GL values were determined using protocols from the FAO/WHO and International Standards Organization recommendations. A total of 152 healthy subjects were enrolled in the study. In all, forty-nine carbohydrate-rich foods were categorised as cereal grains, noodles and pasta, breads and other processed grains and starchy vegetables, prepared using standard cooking methods and evaluated. Cereal grains had the widest range of GI values that the food made with white rice and barley had GI values of 51–93 and 35–70, respectively, according to cooking methods, and most cereal grains had high GL values. Noodles and pasta had low to medium GI values, but most foods had high GL values. Breads had medium to high GI and GL values, while other processed grains had low to medium GI and GL values. The GI values for food made with starchy vegetables (e.g. potatoes and sweet potatoes) varied widely for different cooking methods but tended to have low GL values. In conclusion, GI values for a single food type varied widely with the cooking method used. This study of GI and GL values for common carbohydrate-rich foods provides a valuable reference for consumers and health professionals to make informed food choices for glycaemic control.

Addition of mushroom powder to pasta enhances the antioxidant content and modulates the predictive glycaemic response of pasta

This study reports the effects of addition of mushroom powder on the nutritional properties, predictive in vitro glycaemic response and antioxidant potential of durum wheat pasta. Addition of the mushroom powder enriched the pasta as a source of protein, and soluble and insoluble dietary fibre compared with durum wheat semolina. Incorporation of mushroom powder significantly decreased the extent of starch degradation and the area under the curve (AUC) of reducing sugars released during digestion, while the total phenolic content and antioxidant capacities of samples increased. A mutual inhibition system between the degree of starch gelatinisation and antioxidant capacity of the pasta samples was observed. These results suggest that mushroom powder could be incorporated into fresh semolina pasta, conferring healthier characteristics, namely lowering the potential glycaemic response and improving antioxidant capacity of the pasta.

Obesity and neurological disorders: Dietary perspective of a global menace

Obesity is considered a major public health concern throughout the world among children, adolescents, as well as adults and several therapeutic, preventive and dietary interventions are available. In addition to life style changes and medical interventions, significant milestones have been achieved in the past decades in the development of several functional foods and dietary regimens to reduce this menace. Being a multifactorial phenomenon and related to increased fat mass that adversely affects health, obesity has been associated with the development of several other co-morbidities. A great body of research and strong scientific evidence identifies obesity as an important risk factor for onset and progression of several neurological disorders. Obesity induced dyslipidaemia, metabolic dysfunction, and inflammation are attributable to the development of a variety of effects on central nervous system (CNS). Evidence suggests that neurological diseases such as Parkinson's disease and Alzheimer's disease could be initiated by various metabolic changes, related to CNS damage, caused by obesity. These metabolic changes could alter the synaptic plasticity of the neurons and lead to neural death, affecting the normal physiology of CNS. Dietary intervention in combination with exercise can affect the molecular events involved in energy metabolism and synaptic plasticity and are considered effective non-invasive strategy to counteract cognitive and neurological disorders. The present review gives an overview of the obesity and related neurological disorders and the possible dietary interventions.

Study of the effects of a diet supplemented with active components on lipid and glycemic profiles

OBJECTIVES

Currently, there are numerous studies on risk factors for cardiovascular disease and the potential for functional foods to bring benefits or improve people's health. However, most of these studies are conducted with middle-aged individuals. The aim of this study was to evaluate the effects of supplementing a typical diet with some functional components, which are substances that when consumed in small quantities can improve people's welfare.

METHODS

The participants in this study were young; slightly overweight; had normal glucose tolerance; and had lipid values indicating dyslipidemia or close dyslipidemia. Following a 4-wk run-in phase, participants followed either a diet containing foods enriched with ω-3 fatty acids, β-glucans, phytosterols, and vitamin E or an isoenergetic diet without the active components. Sixteen individuals (age range 20 to 37 y) were randomly assigned to one of two groups. At the end of treatment, while fasting, plasma concentrations of triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total cholesterol were measured. Furthermore, blood glucose was evaluated after fasting and after a meal enriched with β-glucans.

RESULTS

There was a statistically significant reduction (α < 0.05) across the lipid profile. A meal rich in β-glucans produced a glycemic response significantly lower than the nonenriched meal.

CONCLUSION

The dietary supplements used in this work, based on the integration of functional components into the usual diet of the population, have proved effective in reducing peak levels of postprandial glucose and the risk for dyslipidemia. Therefore, these functional components proved a valuable aid in the prevention of cardiovascular diseases and metabolic disorders.

Effect of durum wheat cultivars on physico-chemical and sensory properties of spaghetti

BACKGROUND

Mixtures of different cultivars provide semolina with proper processing properties but not always good nutritional properties. In this study, the effects of mono-varietal cultivars of durum wheat on pasta quality were evaluated in order to find a good balance between nutritional and sensory properties of the final product.

RESULTS

Durum wheat spaghetti was manufactured using semolina from six mono-varietal cultivars. A commercially available semolina mixture was also used to produce a control pasta sample. Instrumental (i.e. rheological and texture analysis), sensory (i.e. elasticity, firmness, adhesiveness) and nutritional (i.e. protein, ash and fibre content, glycaemic index) analyses were carried out. Results highlighted differences between selected cultivars. In particular, spaghetti obtained with Anco Marzio and Cappelli semolina (modern and old cultivars, respectively) showed the highest protein content and the lowest cooking loss, compared with the other samples.

CONCLUSION

Spaghetti made with Cappelli semolina showed the lowest adhesiveness and the highest hardness; it recorded the best overall quality and presented the lowest glycaemic response. Hence, durum wheat pasta with a good balance between nutritional and cooking quality could be obtained from semolina based on mono-varietal cultivars. © 2013 Society of Chemical Industry.

Molecular weight of barley β-glucan influences energy expenditure, gastric emptying and glycaemic response in human subjects

Barley β-glucan (BG) has been shown to reduce glycaemic response (GR) in some studies. It is hypothesised that this reduction may be a function of its physical properties that delay gastric emptying (GE). The effect of these changes in GR and GE on diet-induced thermogenesis (DIT) is not known. The aim of the present study was to assess the effect of BG of different molecular weights and purities on GR, GE and DIT in healthy subjects. This was a randomised, single-blind, repeated-measures design where fifteen healthy subjects were tested on three occasions following an overnight fast. Following the baseline measurements, the volunteers were fed a soup containing high-molecular-weight BG (HBG), a soup containing low-molecular-weight BG (LBG) or a control soup with no BG (CHO). Following the consumption of the breakfast, GR was measured using finger-prick blood samples, GE was determined using the 13C-octanoic acid breath test and DIT was measured using indirect calorimetry. There was a difference in GR AUC between the soups after 60 min but not after 120 min. The CHO and LBG meals had a greater GR than the HBG meal. There were differences in all GE time points, with the HBG meal having the slowest GE time. There was a correlation between the GR and the initial GE times. There were differences in total DIT between the three test meals with the HBG meal having the lowest DIT. The present study indicates that HBG has the ability to delay GE due to increased viscosity, resulting in a decreased GR and DIT.

Glycemic response to carbohydrate and the effects of exercise and protein

OBJECTIVE

The purpose of this study was to investigate the effects of pre-exercise and protein coingestion on the glycemic response to carbohydrates.

METHODS

Twenty-one volunteers (13 males and 8 females) aged 22 y (± 3.8 y) participated in four trials in random order. These included: 1) glucose ingestion at rest (RG), 2) glucose and protein ingestion at rest (RGP), 3) glucose ingestion after exercise (EG), and 4) glucose and protein ingestion after exercise (EGP). Exercise consisted of 45 min of cycling at 60% of participants' age-predicted maximum heart rate. Test drinks contained 50 g glucose or 50 g glucose with 20 g whey protein. Venous blood samples were taken at baseline and subsequently every 15 min for 2 h after drink consumption. Blood plasma was subsequently analyzed for glucose and insulin.

RESULTS

Plasma glucose concentration was significantly lower in the RGP group than in the RG group at 30, 45, 60, and 75 min and in the EGP group than in the EG group at 30, 45, and 60 min (P < 0.05). Plasma insulin area under the curve was significantly higher in the RGP group than in the RG group and in than in the EGP group than in the EG group (P < 0.05). No significant effect of exercise was seen on glycemic or insulinemic responses.

CONCLUSIONS

Coingestion of protein with carbohydrate reduces glycemic response and increases insulinemic response in healthy subjects, whereas pre-exercise seems to have no effect.

Review of human studies investigating the post-prandial blood-glucose lowering ability of oat and barley food products

Oat and barley foods have been shown to reduce human glycaemic response, compared to similar wheat foods or a glucose control. The strength of the evidence supporting the hypothesis that the soluble fibre, mixed linkage β-glucan, reduces glycaemic response was evaluated. A search of the literature was conducted to find clinical trials with acute glycaemic response as an end point using oat or barley products. Of the 76 human studies identified, 34 met the inclusion and exclusion criteria. Dose response and ratio of β-glucan to available carbohydrate as predictors of glycaemic response were assessed. Meals provided 0.3-12.1 g oat or barley β-glucan, and reduced glycaemic response by an average of 48 ± 33 mmol · min/l compared to a suitable control. Regression analysis on 119 treatments indicated that change in glycaemic response (expressed as incremental area under the post-prandial blood-glucose curve) was greater for intact grains than for processed foods. For processed foods, glycaemic response was more strongly related to the β-glucan dose alone (r(2)=0.48, P<0.0001) than to the ratio of β-glucan to the available carbohydrate (r(2)=0.25, P<0.0001). For processed foods containing 4 g of β-glucan, the linear model predicted a decrease in glycaemic response of 27 ± 3 mmol · min/l, and 76% of treatments significantly reduced glycaemic response. Thus, intact grains as well as a variety of processed oat and barley foods containing at least 4 g of β-glucan and 30-80 g available carbohydrate can significantly reduce post-prandial blood glucose.

Food-based ingredients to modulate blood glucose

Maintenance of normal blood glucose levels is important for avoiding chronic diseases such as type 2 diabetes, cardiovascular problems, and obesity. Type 2 diabetes is one of the major health problems affecting the world population and this condition can be exacerbated by poor diet, low physical activity, and genetic abnormalities. Food plays an important role in the management of blood glucose and associated complications in diabetes. This is attributed to the ability of food-based ingredients to modulate blood glucose without causing any adverse health consequences. This chapter focuses on four important food groups such as cereals, legumes, fruits, and spices that have active ingredients such as soluble dietary fiber, polyphenols, and antinutrients with the ability to reduce glycemic and insulin response in humans. Other food ingredients such as simple sugars, sugar alcohols, and some proteins are also discussed in moderation.

Barley cultivar, kernel composition, and processing affect the glycemic index

Barley has a low glycemic index (GI), but it is unknown whether its GI is affected by variation in carbohydrate composition in different cultivars and by food processing and food form. To examine the effect of these factors on GI, 9 barley cultivars varying in amylose and β-glucan content were studied in 3 experiments in separate groups of 10 healthy participants. In Expt. 1, 3 barley cultivars underwent 2 levels of processing: hull removal [whole-grain (WG)] and bran, germ, and crease removal [white pearled (WP)]. GI varied by cultivar (CDC Fibar vs. AC Parkhill, [mean ± SEM]: 26 ± 3 vs. 53 ± 4, respectively; P < 0.05) and pearling (WG vs. WP: 26 ± 4 vs. 35 ± 3, respectively; P < 0.05) with no cultivar × pearling interaction. In Expt. 2, the GI of 7 WG cultivars ranged from 21 ± 4 to 36 ± 8 (P = 0.09). In Expt. 3, WG and WP AC Parkhill and Celebrity cultivars were ground and made into wet pasta. The GI of AC Parkhill pasta (69 ± 3) was similar to that of Celebrity pasta (64 ± 4) but, unlike in Expt. 1, the GI of WP pasta (61 ± 3) was less than that of WG pasta (72 ± 4) (P < 0.05). Pooled data from Expts. 1 and 2 showed that GI was correlated with total fiber (r = -0.75, P = 0.002) but not with measures of starch characteristics. We conclude that the GI of barley is influenced by cultivar, processing, and food form but is not predicted by its content of amylose or other starch characteristics.

Development of functional spaghetti enriched in bioactive compounds using barley coarse fraction obtained by air classification

Barley byproducts obtained by air classification have been used to produce a different barley functional spaghetti, which were compared to different commercial whole semolina samples. Total, insoluble, and soluble fiber and β-glucan contents of the barley spaghetti were found to be greater than those of commercial samples. Furthermore, it was proved that barley spaghetti reached the FDA requirements, which could allow these pastas to deserve the health claims "good source of dietary fiber" and "may reduce the risk of heart disease". When the barley coarse fraction was used, a flavan-3-ols enrichment and an increase of antioxidant activity were reported, while commercial samples showed the absence of flavan-3-ols and a higher presence of phenolic acids and tannins. Whole semolina commercial spaghetti had a significantly higher content of phenolic acids than semolina spaghetti samples. Besides, it was observed that when vital gluten was added to the spaghetti formulation, phenolic compounds were blocked in the gluten network and were partially released during the cooking process.