Relative glycaemic impact of customarily consumed portions of eighty-three foods measured by digesting in vitro and adjusting for food mass and apparent glucose disposal. Br J Nutr. 2010;104:407-417. [PMID: 20338071 DOI: 10.1017/s0007114510000589]

The Potential for the Use of Edible Insects in the Production of Protein Supplements for Athletes

Several types of proteins are used in athletes' supplementation; nevertheless, given the problem of protein deficiency in the world and the growing need for ecological sources of protein, it is very interesting to study the quality of alternative protein sources, such as insect protein. This study investigated the nutritional value, micronutrient content, amino acid profile, and chemical score of banded cricket protein quality in the form of flour, defatted flour, and a protein preparation, as well as popular commercial protein supplements. In addition, in vitro digestion was performed, and the antiradical activity of the hydrolysates was compared. Generally, the defatted cricket flour was the most similar to commercial supplements regarding nutritional value because it contained 73.68% protein. Furthermore, the defatted flour was abundant in essential minerals, such as iron (4.59 mg/100 g d.w.), zinc (19.01 mg/100 g d.w.), and magnesium (89.74 mg/100 g d.w.). However, the protein preparation had an amino acid profile more similar to that of commercial supplements (total content of 694 mg/g protein). The highest antiradical activity against ABTS·+ was noted for the defatted flour (0.901 mM TE/100 g) and against DPPH· for the cricket flour (2.179 mM TE/100 g). Therefore, cricket can be considered an organic protein source for the production of valuable protein supplements.

Stinging Nettle (Urtica dioica L.) as a Functional Component in Durum Wheat Pasta Production: Impact on Chemical Composition, In Vitro Glycemic Index, and Quality Properties

Stinging nettle (Urtica dioica L.) is a good source of biologically active compounds with proven beneficial health effects. This study aimed to investigate the effect of nettle herb supplementation on chemical composition, including the content of selected minerals and pigments, the in vitro glycemic response, and the cooking and sensory quality of extruded pasta. Tagliatelle-shaped pasta was produced under semi-technical scale by partial replacement of durum wheat semolina with 0, 1, 2, 3, 4, and 5% of lyophilized nettle. The partial substitution with freeze-dried nettle caused a statistically significant (p ≤ 0.05) increase in the content of minerals, especially calcium, iron, potassium, and magnesium in the products. The calcium content in the pasta fortified with 5%-addition of stinging nettle was 175.9 mg 100 g⁻¹ and this concentration was 5.8 times higher than in the control sample. At the same time, high content of chlorophylls and carotenoids (237.58 µg g⁻¹ and 13.35 µg g⁻¹, respectively) was noticed. Enriching pasta with a 0–5% addition of stinging nettle resulted in a statistically significant (p ≤ 0.05) increase in the content of the total dietary fiber (TDF) (from 5.1 g 100 g⁻¹ to 8.82 g 100 g⁻¹) and the insoluble dietary fiber (IDF) (from 2.29 g 100 g⁻¹ to 5.63 g 100 g⁻¹). The lowest hydrolysis index of starch (HI = 17.49%) and the lowest glycemic index (GI = 49.31%) were noted for the pasta enriched with 3% nettle.

Nutritional, Physiochemical, and Biological Value of Muffins Enriched with Edible Insects Flour

Edible insects are gaining attention as a novel food; however, studies with their use in food are still limited. This study aimed to determine the chemical composition, physical parameters, sensory acceptance, and biological properties of muffins enriched with different levels of cricket (Gryllodes sigillatus) and mealworm (Tenebrio molitor) flours. The approximate composition was analyzed, along with the physical and textural properties, color, and consumer acceptance. Moreover, the antioxidant properties, starch digestibility, and glycemic index were determined in vitro. As we expected, the protein content in muffins supplemented with insect flour increased, while the carbohydrates content decreased. Moreover, the total phenolic content and antioxidant capacity against ABTS·⁺ and DPPH· increased correspondingly as the percentage of insect flour in the muffins increased. The estimated glycemic index was lower for the fortified muffins than the control (p < 0.05). Additionally, enriched muffins were accepted by consumers, and their taste positively surprised respondents (p < 0.05). Therefore, the results obtained are satisfactory as regards the use of insects for the supplementation of traditional products, and further research into the addition of insects to other nutrient matrices is needed. Furthermore, examining the effect of insect addition on in vivo food biological activity is highly desirable.

Potential contributions of the methodology to the variability of glycaemic index of foods

Glycaemic index (GI) testing provides a useful point of comparison between carbohydrate sources. For this comparison to be meaningful, the methods used to determine GI values need to be rigorous and consistent between testing events. This requirement has led to increasing standardization of the GI methodology, with an international standard developed in joint consultation with FAO/WHO (ISO 26642:2010) currently the most up to date document. The purpose of this review is to compare the international standard to methods of published studies claiming to have performed a GI test. This analysis revealed that the international standard permits a wide range of choices for researchers when designing a GI testing plan, rather than a single standardized protocol. It has also been revealed that the literature contains significant variation, both between studies and from the international standard for critical aspects of GI testing methodology. The primary areas of variation include; what glucose specification is used, which reference food is used, how much reference food is given, what drink is given during testing, the blood sampling site chosen and what assay and equipment is used to measure blood glucose concentration. For each of these aspects we have explored some of the methodological and physiological implications of these variations. These insights suggest that whilst the international standard has assisted with framing the general parameters of GI testing, further stan-dardization to testing procedures is still required to ensure the continued relevance of the GI to clinical nutrition.

Nutritional, Physiochemical, and Antioxidative Characteristics of Shortcake Biscuits Enriched with Tenebrio molitor Flour

Edible insects, due to their high nutritional value, are a good choice for traditional food supplementation. The effects of partial replacement of wheat flour and butter with mealworm flour (Tenebrio molitor) on the quality attributes of shortcake biscuits were studied. The approximate composition was analyzed, along with the physical properties and color. Moreover, the antioxidant properties, starch digestibility, and glycemic index were determined in vitro. The protein and ash contents in biscuits supplemented with mealworm flour increased, while the carbohydrates content decreased. The increasing insect flour substitution decreased the lightness (L*) and yellowness (b*) but increased the redness (a*), total color difference (ΔE), and browning index (BI). The spread factor for the sample with the highest proportion of mealworm flour was significantly higher than the other biscuits. Furthermore, higher additions of mealworm flour increased the antioxidant activity of the biscuits and contributed to an increase in the content of slowly digested starch, with a decrease in the content of rapidly digested starch. Therefore, the results of the research are promising and indicate the possibility of using edible insects to enrich food by increasing the nutritional and health-promoting values.

The Physicochemical Characterization of Unconventional Starches and Flours Used in Asia

Starches and flours used commonly in Asia (tapioca, sweet potato, sago, water chestnut, and high amylose maize starch, red rice and kithul flour) were characterized in terms of their chemical composition, morphological, functional, pasting, thermal, gelling and in vitro digestibility properties. It was observed that the differences in their chemical composition and structure influenced their properties. High amylose maize was the most stable, thus it required the highest gelatinization temperature which was observed in both the differential scanning calorimetry (DSC) and pasting profiles. Kithul flour had a significantly lower rate of digestion (p < 0.05) than the other samples (except for high amylose maize starch). Unlike high amylose maize starch, it had a gelatinization temperature that could be achieved during cooking, and had good gelling properties.

Quality, functional and sensory evaluation of pasta fortified with extracts from Opuntia ficus-indica cladodes

BACKGROUND

The stems of Opuntia ficus-indica, known as cladodes, are a rich source of soluble fibers, which makes them an important candidate for the production of functional foods. Tagliatelle of durum wheat fortified with Opuntia cladode extract (OCE) at different levels of addition (10-30%, v/w) was prepared on a laboratory scale and quality characteristics and sensory acceptability were assessed.

RESULTS

The main quality parameters (optimal cooking time, swelling index, cooking loss, dry matter) and sensory analysis on a nine-point hedonic scale were comparable with those of the control pasta sample (no added OCE) when durum wheat was supplemented with OCE at up to 20% (v/w). An in vitro human simulated gastrointestinal digestion in the presence of cholesterol or its main dietary oxidized derivative, 7-ketocholesterol, showed that OCE-fortified pasta strongly reduced the bioaccessibility of both the sterols (the higher the incorporated OCE level, the higher the effect). Moreover the extent of starch digestion decreased with increasing levels of OCE.

CONCLUSION

The results of the present study indicate that OCE-fortified pasta comprises a food with healthy properties, such as blood cholesterol- and glucose-lowering capabilities. © 2019 Society of Chemical Industry.

Total antioxidant capacity and starch digestibility of muffins baked with rice, wheat, oat, corn and barley flour

Muffins are a popular snack consumed in western and emerging countries. Increased glycemic load has been implicated in the aetiology of diabetes. This study examined the starch digestibility of muffins baked with rice, wheat, corn, oat and barley flour. Rapidly digested starch (RDS) was greatest in rice (445 mg/g) and wheat (444 mg/g) muffins, followed by oat (416 mg/g), corn (402 mg/g) and barley (387 mg/g). Total phenolic content was found to be positively correlated with total antioxidative capacity and inversely related to the RDS of muffins. The phenolic content was highest in muffin baked with barley flour (1,687 μg/g), followed by corn (1,454 μg/g), oat (945 μg/g), wheat (705 μg/g), and rice (675 μg/g) flour. Browning was shown not to correlate with free radical scavenging capacity and digestibility of muffins. The presence of high phenolic content and low RDS makes barley muffin an ideal snack to modulate glycemic response.

In vitro utilization of gold and green kiwifruit oligosaccharides by human gut microbial populations

We examined the effects of whole kiwifruit on gut microbiota using an in vitro batch model of gastric-ileal digestion and colonic fermentation. Faecal fermentations of gold and green kiwifruit, inulin and water (control) digests were performed for up to 48 h. As compared to the control, gold and green kiwifruit increased Bifidobacterium spp. by 0.9 and 0.8 log(10) cfu/ml, respectively (P < 0.001), and the Bacteroides-Prevotella-Porphyromonas group by 0.4 and 0.5 log(10) cfu/ml, respectively. Inulin only had a bifidogenic effect (+0.4 log(10) cfu/ml). This was accompanied with increases in microbial glycosidases, especially those with substrate specificities relating to the breakdown of kiwifruit oligosaccharides, and with increased generation of short chain fatty acids. The microbial metabolic activity was sustained for up to 48 h, which we attribute to the complexity of the carbohydrate substrate provided by whole kiwifruit. Kiwifruit fermenta supernatant was also separately shown to affect the in vitro proliferation of Bifidobacterium longum, and its adhesion to Caco-2 intestinal epithelial cells. Collectively, these data suggest that whole kiwifruit may modulate human gut microbial composition and metabolism to produce metabolites conducive to increased bifidobacteria-host association.

Glycemic impact as a property of foods is accurately measured by an available carbohydrate method that mimics the glycemic response

The relative glycemic impact (RGI), the weight of glucose that would induce a glycemic response equivalent to that induced by a given amount of food, is preferably expressed for reference amounts of foods customarily consumed per eating occasion. But because customarily consumed portions of different foods deliver different glycemic carbohydrate doses, methods for determining their RGI need to allow for homeostatic responses to different glycemic carbohydrate loadings. We tested the accuracy of an in vitro method for measuring the RGI of customarily consumed portions that allows for homeostasis, using 24 foods. Glucose equivalents released during simulated gastrointestinal digestion were adjusted by the glycemic potency of contributing sugars to obtain cumulative glycemic glucose equivalents (GGE) and multiplied by food portion weight. Corresponding dose-dependent blood glucose clearance was calculated and subtracted from GGE, giving net GGE compared with time curves reminiscent of blood glucose response curves. RGI values (GGE content) for the food portions were obtained by comparing incremental areas under the curves for foods with that for a white bread reference of known GGE content. The correlation between in vivo values calculated from glycemic index values for the same foods and in vitro values was: in vivo GGE = 1.0 in vitro GGE - 0.5; R2 = 0.90. Bland-Altman methods comparison analysis showed close agreement: in vivo GGE = -0.055 in vitro GGE + 1.16; R2 = 0.027. The results suggest that a modified available carbohydrate determination can economically provide valid RGI values for consumer and industry use.