Physicochemical properties of expanded extrudates from colored sorghum genotypes

Exploring the potential of sorghum with reference to its bioactivities, physicochemical properties and potential health benefits

Sorghum, belonging to the Poaceae family, is a widely consumed grain, particularly in Africa. Sorghum grains have been used in traditional African diets for centuries. These grains, along with their products, are known for their high nutritional value and possess various bioactive properties, including antioxidant, anti-obesity, anti-diabetic, anti-cardiovascular, anti-inflammatory, antimicrobial, and anticancer activities. Despite these benefits, sorghum grains face challenges due to the presence of certain anti-nutritional components such as tannins, phytates, trypsin inhibitors, and protein crosslinkers. Processing techniques such as soaking, germination, fermentation, thermal processing, and irradiation can improve the nutritional quality of sorghum by reducing anti-nutritional factors. Among these, fermentation, particularly when combined with other methods like soaking and germination, is considered most effective in enhancing the grain's nutritional value. This review addresses the current knowledge gaps regarding sorghum's nutritional and phytochemical composition and its potential health benefits. It also emphasizes the importance of further research to enhance sorghum's inherent nutritional attributes and promote its use as a sustainable crop to address global food security challenges. The findings highlight sorghum's potential in improving dietary quality and contributing to better health outcomes worldwide.

Effects of acute consumption of a beverage based on extruded whole-grain pearl millet flour on glycemic and insulinemic control, food intake, and appetite sensation in eutrophic adults: A randomized cross-over clinical trial

OBJECTIVES

Whole-grain pearl millet is a nutritious cereal source of dietary fiber, vitamins, minerals, and bioactive compounds. It offers health benefits such as glycemic control and satiety. Extrusion cooking for diverse formulations, including beverages, can alter its chemical composition, impacting the nutritional value. This study aimed to evaluate the sensory acceptability of an extruded millet flour beverage and its acute effects on glycemic index (GI), glycemic and insulinemic response, food intake, and subjective appetite sensations in euglycemic and eutrophic adults.

METHODS

This is an acute, single-blind, randomized, controlled, cross-over clinical study comprising 14 euglycemic and eutrophic adults. Initially, beverages based on whole extruded millet flour were developed, and sensorially and chemically analyzed. Next, a clinical trial was conducted with participants undergoing four sessions and consuming one of the following options: extruded millet beverage, a maltodextrin control beverage, or a glucose solution administered in two separate sessions. Blood glucose, insulin, and appetite responses were assessed over a 2-h period, in addition to determining the GI of the beverages and analyzing food intake in the 24 h following each session.

RESULTS

The extruded millet flour strawberry-flavored beverage had the best sensory acceptance and was classified as having as high GI. Consumption of the extruded millet beverage showed similar glycemic and insulinemic responses, as well as appetite control and food intake of the subjects, when compared with consumption of the maltodextrin control beverage.

CONCLUSIONS

Intake of the extruded millet beverage maintained glycemic and insulinemic responses, appetite control, and food intake in euglycemic and eutrophic subjects.

Physicochemical, calorimetric and texture profile characteristics of various gluten-free flours

It is important to understand how the composition and structure of proteins from other flours differ from proteins in wheat, in order to have a better option to substitute gluten products with gluten-free food products. The aim of this study was the characterization of gluten-free flours and comparison of their rheological and calorimetric properties against wheat flour, for its use as gluten-free alternative. Chemical composition analysis, water solubility index (WSI), water absorption index (WAI), texture and calorimetric profile were determined. The closest WAI to wheat flour (1.45 g gel/g sample) was corn flour (2.41 g gel/g sample), while the WSI of chickpea flour was 5.51% approaching that of wheat flour of 5.88%. The hardness and adhesiveness values closest to wheat (1.65 kgf and 0.03 mJ) were amaranth flour with 0.85 kgf and 0.01 mJ, respectively. The phenolic content and antioxidant capacity were higher in the corn and bean flours with 244.4 mg GAE/100 g, 148 mg GAE/100 g and 190 mg AAE/100 g and 170 mg AAE/100 g, respectively. The combination of these non-conventional flours can be an innovative source of gluten-free formulas.

Extrusion of process flavorings from methionine and dextrose using modified starch as a carrier

This study aimed to produce process flavorings from methionine and glucose via Maillard reaction by extrusion method. Modified starch was used as a carrier to reduce the torque and facilitate the production process. Five formulations of process flavorings with different ratios of methionine: dextrose: modified starch: water as MS5 (72:18:5:5), MS15 (64:16:15:5), MS25 (56:14:25:5), MS35 (42:12:35:5), and MS45 (40:10:45:5) were prepared and feded into the extruder. The temperatures of the extruder barrel in zones 1 and 2 were controlled at 100, and 120°C, with a screw speed of 30 rpm. The appearance of the obtained products, torque, pH before and after extrusion, color, volatile compounds, and sensory evaluation were determined. The extrudate from the formulation containing the highest amount of modified starch (MS45) gave the highest L* (lightness) of 88.00, which increased to 93.00 (very light) after grinding into a powder. The process flavorings from all formulations exhibited similar sensory scores in terms of aroma, taste, and water solubility, with a very slight difference in color. However, MS25, MS35 and MS45 indicated the torque at 10 Nm/cm3, while MS5 and MS 15 exhibited higher torque at 18, and 25 Nm/cm3, respectively. Extruded process flavorings from MS25 were analyzed for their flavor profiles by gas chromatography-mass spectrometry. Twelve volatile compounds including the key volatile compounds for sulfurous and vegetable odor type, dimethyl disulfide, methional, and methanethiol, were found. Four pyrazine compounds presented nutty, musty and caramelly odor; and 3-hydroxybutan-2-one and heptane-2,3-dione, which gave buttery odor type, were also detected. The results demonstrated a successful production of process flavorings using modified starch as carrier to facilitate and reduce the torque during the extrusion process.

Andean purple maize to produce extruded breakfast cereals: impact on techno-functional properties and sensory acceptance

BACKGROUND

Andean purple maize (APM) is an ancient crop widely used as a natural coloring in traditional Peruvian cuisine. However, it has been little explored within the food industry. The present study assessed how APM impacts on techno-functional properties and sensory acceptance of breakfast cereals. Extruded samples formulated with 100, 75, 50, and 25% APM, and complemented with yellow corn grits (YCG), were analyzed for their techno-functional and sensory properties.

RESULTS

Increases in bulk density, as well as reduction in the expantion and porosity were observated for extrudates containing ≥ 50% APM, accompanied by an increase in purple color intensity. Increase in milk absorption index, reduction in milk solubility index and decrease in cereal hardness with increase in APM were also observed. Despite this, APM extented the cereal bowl-life. High sensory scores of overall liking (6) and color (7) were obtained for extruded formulations containing ≥ 50% APM and low values for extrudates with 25% APM. Aroma, flavor, and texture scores did not present significant differences.

CONCLUSION

APM is an ingredient with the potential to be used to produce breakfast cereals since it improves their techno-functional characteristics and sensory acceptance, at the same time, it leads to the production of healthy, nutritious, and sustainable food. © 2022 Society of Chemical Industry.

A review of extrusion-modified underutilized cereal flour: chemical composition, functionality, and its modulation on starchy food quality

Compared with three major cereals, underutilized cereals (UCs) are those with less use but having abundant bioactive components and better functionalities after proper processing. As a productive and energy-efficient technology, extrusion has been used for UC modification to improve its technological and nutritional quality. Extrusion could induce structural and quantitative changes in chemical components of UC flour, the degree of which is affected by extrusion intensity. Based on the predominant component (starch), functionalities of extruded underutilized cereal flour (EUCF) and potential mechanisms are reviewed. Considering bioactive compounds, it also summarizes the physiological functions of EUCF. EUCF incorporation could modulate the dough rheological behavior and starchy foods quality. Controlling extrusion intensity or incorporation level of EUCF is vital to achieve sensory-appealing and nutritious products. This paper gives comprehensive information of EUCF to promote its utilization in novel staple foods.

Effects of Dry Heat Treatment and Milling on Sorghum Chemical Composition, Functional and Molecular Characteristics

This study aimed to highlight the effects of grains dry heat treatment, flour particle size and variety on sorghum flour nutritional, functional, and molecular characteristics. The results obtained showed that dry heat treatment led to fat, fiber and water absorption capacity increase, while the moisture, protein, ash, water retention capacity, solubility index, foaming capacity, and FT-IR absorption bands characteristic to phytic acids decreased with temperature applied raised. Particle size reduction determined lower protein, solubility index, and emulsifying activity and higher fat content, oil absorption capacity, swelling power, and foaming capacity. White sorghum flour fractions presented lower protein content, except when they were treated at 140 °C, lower carbohydrates and fibers and higher fat content compared to those made of red sorghum. Moderate significant correlations (p < 0.05) were observed between some of the functional properties and proximate composition of flours. Thus, both dry heat treatment conditions and particle size exerted significant influences of sorghum flour chemical and functional properties. These results showed the importance of particle size and dry heat treatment on sorghum flours functionality, being helpful for further optimizations and choices for bakery products use.

Evaluation of Edible Quality of Sorghum Based on Principal Component Analysis

Sorghum (Sorghum bicolor (L.) Moench) is one of the most important cereals in the Northeast China. The physicochemical, pasting, texture, and cooking properties of 21 sorghum varieties were determined, which were mainly cultivated in Northeast China. Then, the evaluation of edible quality of sorghum was based on principal component analysis and fitted with the score of sensory evaluation. Five principal components (PCs) with a cumulative contribution rate of 86.19% could be picked out to describe the taste, pasting, flavor, cooking, and variety of sorghum, respectively. And a comprehensive equation of sorghum edible quality in Northeast China was constructed which was Z = 0.45F1 + 0.25F2 + 0.12F3 + 0.10F4 + 0.08F5. The edible quality of No. 14 and No. 15 was the best. The sensory evaluation was used to verify the above equation with the fitting coefficient of 0.81, which indicated that the equation could be more accurate to evaluate the edible quality of sorghum in Northeast China.

Extruded sorghum (Sorghum bicolor L.) reduces metabolic risk of hepatic steatosis in obese rats consuming a high fat diet

The study investigated the effect of extruded sorghum flour (ESF) in a high fat diet (HFD) on biometric measurements and hepatic lipogenesis. Male Wistar rats were fed a normal diet (AIN-93M), HFD, HFD plus ESF replacing 50% cellulose and 100% corn starch (HFDS50), or HFD plus ESF replacing 100% cellulose and 100% corn starch (HFDS100) for eight weeks. ESF reduced the body mass index and liver weight of obese rats. Additionally, ESF reduced hepatic lipogenesis by increasing adiponectin 2 receptor gene expression and gene and protein expressions of peroxisome proliferator-activated receptor α (PPARα), while reducing the gene expression of sterol regulatory element-binding transcription factor 1. Molecular docking analysis revealed the affinity of ESF compounds (luteolinidin, apigeninidin, 5-methoxy-luteolinidin, and 7-methoxy-apigeninidin) with the PPAR-α receptor. Histological analysis confirmed the decreased grade of hepatic steatosis in obese rats. These data indicate the potential of ESF to reduce metabolic risk of hepatic steatosis associated with lipogenesis and obesity.

Use of Red Cactus Pear (Opuntia ficus-indica) Encapsulated Powder to Pigment Extruded Cereal

Encapsulated powder of the red cactus pear is a potential natural dye for the food industry and a known antioxidant. Although the use of this powder is possible, it is not clear how it alters food properties, thus ensuing commercial acceptability. The aim of this study was to evaluate the effect of encapsulated powder of the red cactus pear on the physicochemical properties of extruded cereals. The powder was mixed (2.5, 5.0, and 7.5% w/w) with maize grits and extruded (mix moisture 22%, temperature 100°C, and screw speed 325 rpm). The physical, chemical, and sensory characteristics of the extruded cereal were evaluated; extruded cereal without encapsulated powder was used as a control. All cereal extrudates pigmented with the encapsulated powder showed statistically significant differences (P<0.05) in expansion, water absorption, color, density, and texture compared to the control. The encapsulated powder had a positive effect on expansion and water absorption indices, as well as color parameters, but a negative effect on density and texture. Extruded cereal properties were significantly (P<0.05) correlated. Sensorially, consumers accepted the extruded cereal with a lower red cactus pear powder content (2.5% w/w), because this presented characteristics similar to extruded cereal lacking pigment.

Comparing sorghum and wheat whole grain breakfast cereals: Sensorial acceptance and bioactive compound content

The sensory acceptance and the content of bioactive compounds of whole-sorghum and whole-wheat breakfast cereals were compared. Sensory acceptance was assessed using the Food Action RatingScale. 3-Deoxyanthocyanidins, flavones and flavanones were determined by high-performance liquid chromatography (HPLC) with diode array detection, and vitamin E by HPLC with fluorescence detection. Total phenolics and antioxidant activity were determined by spectrophotometry. The sorghum breakfast cereal had better sensory acceptance (70.6%) than wheat breakfast cereal (41.18%). Sorghum had higher 3-deoxyanthocyanidin content (100% higher), total phenolic compounds (98.2% higher) and antioxidant activity (87.9% higher) than wheat breakfast cereal. Flavones and flavanones were not detected in both breakfast cereals. Total vitamin E content was 78.6% higher in wheat than in sorghum breakfast cereal. Thus, consumption of whole sorghum breakfast cereal should be encouraged, since it had good sensory acceptance and is a source of bioactive compounds that can promote benefits to human health.

Consumption of a drink containing extruded sorghum reduces glycaemic response of the subsequent meal

PURPOSE

Glycaemic control is essential to prevent the manifestation of diabetes in predisposed individuals and the development of associated comorbidities. It is believed that sorghum may modulate the glucose response. In this study, we investigated the effect of extruded sorghum consumption, and the profile of bioactive compounds, on postprandial glycaemia of a subsequent meal in normal weight and normoglycaemic subjects.

METHODS

This was a randomized, single-blind, crossover designed study. After a 12 h overnight fasting, ten subjects reported to the laboratory to participate in four experimental sessions, and consumed one of three sorghum test drinks: sorghum P 3-DXAs (with proanthocyanidins-P and rich in 3-deoxyanthocyanidins-3-DXAs); 3-DXAs (without proanthocyanidins and rich in 3-DXAs); and control (low in 3-DXAs and without proanthocyanidins); or a non-sorghum drink. 30 min later, the subjects consumed a glucose solution (25 g glucose). Glycaemic response was monitored at times 0 (before glucose solution), 15, 30, 45, 60, 90, 120 min (after glucose solution consumption). The incremental areas under the glycaemic curve (iAUC) were calculated by the trapezoidal method.

RESULTS

Intake of P 3-DXAs drink before the glucose solution resulted in a postprandial iAUC lower than the other sorghum test drinks. Sorghum drinks minimized the postprandial glycaemia peak.

CONCLUSION

Sorghum drinks consumption, especially the P 3-DXAs drink, 30 min before the glucose solution resulted in lower iAUC compared to the non-sorghum drink, leading to a lower glycaemic response.