Researchers from the Quadram Institute and King’s College London have shown that replacing wheat flour with a new ingredient derived from chickpeas improved the glycaemic response of people eating white bread.
The ingredient uses specially developed milling and drying processes that preserves cellular structure, making its starch more resistant to digestion.
Developing food products that contain more of this resistant starch would help to control blood glucose levels and reduce risk of type 2 diabetes.
Starch from wheat is a major source of dietary carbohydrate, but in bread and many other processed foods it is quickly digested to glucose in the body, causing a large spike in blood glucose levels.
There is a large body of evidence that links long-term consumption of foods that provoke high glycaemic responses to the development of Type II diabetes.
With this condition on the rise, along with obesity and other metabolic disorders, providing foods and ingredients that help consumers better manage blood glucose could help combat these challenges to health.
Many pulses, such as chickpeas, peas, beans and lentils naturally contain high amounts of resistant starch, which is digested slowly and avoids potentially damaging blood glucose spikes.
But most of this beneficial resistance is lost, rendering the starch highly digestible, when these crops are milled to flour and processed into a food product.
For this reason, the scientists invented an alternative milling process, which preserves the plant cell wall structures (dietary fiber) that surround the starch.
This ‘Type 1’ resistant starch is the same as that found in wholefoods, but this new ingredient can be used in a form that potentially allows it to be incorporated into a wider range of foods.
Funding from the Biotechnology and Biological Sciences Research Council (BBSRC), part of UKRI, was used to develop the commercial potential of this novel ingredient, referred to as PulseON, and expands the possibilities for including large amounts of resistant starch in processed foods to improve nutritional quality.
And now, in a new study published in the journal Food Hydrocolloids, the research team shows for the first time that the resistant property of the starch is retained during bread making, and that people who ate bread rolls where some wheat flour was replaced by PulseON had lower blood glucose responses.
In a double blind randomized cross over study, the scientists replaced 0%, 30% or 60% of the wheat flour in a standard white wheat bread recipe with PulseON.
Healthy human participants consumed each type of bread roll type for breakfast in random order on separate days, with no knowledge of which type of roll they were eating. Their glucose levels were recorded using continuous glucose monitors.
Blood glucose responses to the PulseON enriched breads were on average 40% lower than after eating the control breads.
All bread rolls contained similar amounts of starch and wheat protein (gluten) per serving, so the different blood glucose responses reflect the carbohydrate quality.
These results raise the possibility of using such foods for improving the dietary management of diabetes, which needs to be evaluated in future studies.
The digestion of starch in each bread type was also studied in a laboratory using biochemical and microscopy techniques. These experiments showed that after two hours of digestion, the wheat starch had been digested, but the type-1-resistant starch remained.
This confirms that the lower glucose response to PulseON enriched breads was due to the resistant starch enclosed in the chickpea ingredient not being digested.
“Incorporating our new type of flour into bread and other staple foods provides an opportunity to develop the next generation of low glycaemic food products to support public health measures to improve health through better diets” said Dr. Cathrina Edwards from the Quadram Institute.
“Consumers replacing wheat bread with PulseON enriched bread would benefit not only from the type 1 resistant starch, but also from the higher fiber and protein content.”
For widespread acceptance, the qualities of the products such as their taste, texture and appearance need to match those that are so popular with consumers.
Participants gave the PulseON enriched breads similar scores for texture and taste as the white bread. Quality tests indicated that any effects on bread quality (texture, appearance) were subtle and most noticeable when large amounts of PulseON were used.
The sensory properties need to be confirmed with a broader consumer group in a non-clinical setting, but are very encouraging for efforts to produce healthier white bread without adverse effect on product quality.
The technology is patent-protected and the group are looking at commercial exploitation. Previous research from the same group has shown that the same milling process may be applied to other beans, lentils and pulses, resulting in cellular powders high in resistant starch, but with different colors and flavors. The researchers are now exploring ingredient applications in a broader range of food products, and planning further trials involving those with prediabetes and type 2 diabetes.
Snacking remains a major component in the dietary patterns of most Americans despite the ongoing controversy as to whether eating between and/or replacing meals with smaller eating occasions is a “healthful” habit. Whereas snacking can contribute to detrimental weight gain by promoting the consumption of empty calories, recent evidence supports the role of nutrient-dense snacking to promote health (1).
There are several snacking strategies that improve indices of weight management. Specifically, increased appetite control, increased satiety, and reduced unhealthy snacking have been reported with the consumption of higher-protein snacks (2–7), higher-fiber snacks (see review in reference 8); and those that have a lower glycemic index (9).
Another important aspect of health includes the ability to improve and/or maintain glucose control throughout the day. Although limited, 1 study reported improvements in postprandial glycemic control with a snack that had a lower glycemic index (9). Collectively, further work is needed to explore the effects of commonly consumed snacks on these health outcomes.
The consumption of hummus has increased in the United States and globally over the past few years (10). Due to the low glycemic index properties (11), high nutritive value (11), and palatability of hummus, it is plausible that the inclusion of this food into an afternoon snack might result in improvements in diet quality, ingestive behavior, and glycemic control.
Thus, the purpose of this study was to determine whether a lower-sugar afternoon hummus snack compared with a common higher-sugar snack improves diet quality, appetite, satiety, and glycemic control compared with no snacking in healthy adults.
Discussion
The acute consumption of a lower-sugar, afternoon hummus snack improved diet quality through reductions in high-sugar desserts and increases in vegetable consumption compared with a higher-sugar afternoon snack and/or no afternoon snack. Additionally, hummus snacking led to improvements in selected indices of appetite, satiety, mood, and glycemic control compared with higher-sugar snacking and/or no afternoon snacking.
These data suggest that the daily consumption of a low-sugar snack containing hummus might be a potential strategy to improve diet quality and selected health outcomes in adults.
Over the past few decades, between-meal snacking has become increasingly popular. Frequency of snacking has increased from 1 snack/d to 2.2 snacks/d in the last 4 decades (14, 15), and snacks are now responsible for about 24% of daily energy intake in US adults (14).
Although increased snacking often results in an increase in eating frequency throughout the day, it does not always increase daily energy intake if it is compensated for by decreased portion sizes in subsequent eating occasions (16). However, many popular snacks are energy dense, contain “empty calories,” and elicit weak postprandial satiety (2, 17–19). Thus, increased snacking frequency can result in excess daily energy intake (17, 18).
In the current study, regardless of snack quality, the addition of an ingestive event in the form of an afternoon snack did not increase daily caloric intake. However, better dietary compensation observed following the HUMMUS snack compared with the BARS suggests that the type of snack consumed influences subsequent energy intake.
High-glycemic foods are digested and absorbed quickly and can promote overeating (20). Alternately, low-glycemic foods, like hummus, are digested and absorbed more slowly and can promote weight management through increased satiety and subsequent reductions in food intake (21, 22).
Traditional hummus is a creamy dip prepared by mixing cooked, mashed chickpeas with other ingredients such as tahini, olive oil, garlic, lemon juice, and various spices (23). Legumes such as the chickpeas found in hummus are low glycemic, with a mean glycemic index score of 28 ± 9/100 on the glucose reference scale, which has a maximum score of 100 (21).
Besides being low glycemic, chickpeas and other legumes are also high in fiber and have a high ratio of slowly digestible starch to readily digestibly starch (24). Legume consumption provides several health benefits, including increased satiety, improved body weight, and prevention of diseases such as type 2 diabetes and cardiovascular disease (23).
Most studies that have investigated appetite and satiety following legume consumption are short-term, single-bolus feeding trials. In these studies, legume consumption within a meal appears to reduce postprandial hunger and increase satiety but has little to no effect on second meal intake when compared with energy-controlled comparison foods such as white bread or cereal grains (25, 26). In a long-term study by Murty et al. (27), legume consumption and satiation were assessed before and after 12 wk of chickpea supplementation (104 g/d).
The addition of chickpeas into the habitual diet resulted in higher satiation ratings compared with habitual diets in healthy adults. The findings from this study are in line with the current body of evidence supporting the consumption of legumes, as hummus, for improved appetite control and satiety (26, 27).
In addition to the improvements in appetite and satiety, short-term studies report that the consumption of beans, chickpeas, and other legumes reduces postprandial glucose elevation compared with other carbohydrate foods (28). Further, a meta-analysis found that consuming legumes daily for >4 wk results in significantly lower fasting blood glucose and insulin (29). However, much less research has been conducted on hummus and its effect on glycemic response.
One previous study illustrated lower postprandial blood glucose concentrations in the hour after hummus consumption compared with white bread consumption (11). Similarly, the present study found that the HUMMUS snack improved the afternoon glycemic response when compared with a higher-sugar BARS snack.
This is an especially important consideration for people who struggle with glycemic control, such as type 2 diabetics. Previous studies have found that legume consumption improves glycemic control in diabetics (29, 30), which indicates that hummus might present a healthy, risk-reducing snack option for these individuals.
reference link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398782/
More information: Balazs H. Bajka et al. The impact of replacing wheat flour with cellular legume powder on starch bioaccessibility, glycaemic response and bread roll quality: A double-blind randomised controlled trial in healthy participants, Food Hydrocolloids (2020). DOI: 10.1016/j.foodhyd.2020.106565
