Impact of the soak and the malt on the physicochemical properties of the sorghum starches

Effects of soaking glutinous sorghum grains on physicochemical properties of starch

Glutinous sorghum grains were soaked (60-80 °C, 2-8 h) to explore the effects of soaking, an essential step in industrial processing of brewing, on starch. As the soaking temperature increased, the peak viscosity and crystallinity of starch gradually decreased, while the enzymatic hydrolysis rate and storage modulus first increased and then decreased. At 70 °C, the content of amylose, the enzymatic hydrolysis rate of starch, and the final viscosity first increase and then decrease with the increase of soaking time, reaching their maximum at 6 h, increased by 53.1 %, 11.0 %, and 10.4 %, respectively, as compared with the non-soaked sample. At 80 °C (4 h), the laser confocal microscopy images showed a network structure formed between the denatured protein chains and the leached-out amylose chains. The molecular weights of starch before and after soaking were all in the range of 3.82-8.98 × 107 g/mol. Since 70 °C is lower than that of starch gelatinization and protein denaturation, when soaking for 6 h, the enzymatic hydrolysis rate of starch is the highest, and the growth of miscellaneous bacteria is inhibited, which is beneficial for subsequent processing technology. The result provides a theoretical basis for the intelligent control of glutinous sorghum brewing.

Effect of malting on physicochemical, antioxidant, and microstructural properties of finger millet (Eleusine coracana) flours

Finger millet (Eleusine coracana L. Gaertn.) is a gluten-free crop with a high amount of fiber, calcium and iron, outstanding malting qualities and a low glycemic index. The study aimed to determine the physicochemical, functional, antioxidant and microstructural properties of malted finger millet (light and dark brown) flours. The two varieties of finger millet grains were germinated for 0, 24, 48 and 72 h and kilned for 8 h. The lightness (L*) values of malted finger millet flours significantly increased, with light brown having the highest L* value of 76.62. The hue angle and total color differences (ΔE) of the malted finger millet flours increased significantly (p ≤ .05.), and values ranged from 63.43° to 71.20° (light brown) and 2.12° to 4.32° (dark brown), respectively. The moisture, ash, fiber, protein, total phenolic, total flavonoids contents and DPPH activity of both malted finger millet flours significantly increased. On the contrary, the fat, carbohydrate, energy contents and FRAP activity significantly decreased with each malting period of both finger millet flours. Both malted finger millet flours' solubility index, water and oil absorption capacity increased significantly while the packed and loose bulk density decreased. Malting had no significant effect on the viscosity of the cold paste; however, a significant decrease in the viscosity of the cooked paste in both finger millet flours was observed, with values ranging from 285 to 424.00 cP (light brown) and 271.33 to 418.00 cP (dark brown), respectively. Malting resulted in changes in the thermal properties of finger millet flours with an increase in the onset, peak and conclusion temperatures. Fourier-Transform Infrared Spectra showed that malting slightly changed the peaks of both finger millet flours. Scanning electron microscopy showed that malting altered the microstructural characteristics of finger millet flours. The results showed that malted finger millet flours are promising raw materials for gluten-free bakery products.

Sorghum Flour and Sorghum Flour Enriched Bread: Characterizations, Challenges, and Potential Improvements

A Sorghum flour (SF) is a leading and prominent food source for humans in African countries. Recently extensive studies have been conducted on Sorghum bread (SB) or sorghum composite bread (SCB), covering various aspects. However, there are many technical challenges in the formation of SF and sorghum composite flour (SCF) that impact the quality of the bread and fail to meet the consumer's desires and expectations. This review primarily focuses on the characteristics of SF, SCF, SB, and SCB, with discussions encompassing the rheological and morphological properties of the dough, improvement strategies, and bread quality. Moreover, a comprehensive analysis has been conducted to investigate the behavior of SF and SCF along with a discussion of the challenges affecting bread quality and the strategies applied for improvement. The significant demand for nutrients-rich and gluten-free bread indicates that sorghum will become one of the most vital crops worldwide. However, further comprehensive research is highly demanded and necessary for an in-depth understanding of the key features of SF and the resulting bread quality. Such understanding is vital to optimize the utilization of sorghum grain in large-scale bread production.

Combined ultrasound and germination treatment on the fine structure of highland barley starch

Highland barley is a grain crop grown in Tibet, China. This study investigated the structure of highland barley starch using ultrasound (40 kHz, 40 min, 165.5 W) and germination treatments (30℃ with 80% relative humidity). The macroscopic morphology and the barley's fine and molecular structure were evaluated. After sequential ultrasound pretreatment and germination, a significant difference in moisture content and surface roughness was noted between highland barley and the other groups. All test groups showed an increased particle size distribution range with increasing germination time. FTIR results also indicated that after sequential ultrasound pretreatment and germination, the absorption intensity of the intramolecular hydroxyl (-OH) group of starch increased, and hydrogen bonding was stronger compared to the untreated germinated sample. In addition, XRD analysis revealed that starch crystallinity increased following sequential ultrasound treatment and germination, but a-type of crystallinity remained after sonication. Further, the Mw of sequential ultrasound pretreatment and germination at any time is higher than that of sequential germination and ultrasound. As a result of sequential ultrasound pretreatment and germination, changes in the content of chain length of barley starch were consistent with germination alone. At the same time, the average degree of polymerisation (DP) fluctuated slightly. Lastly, the starch was modified during the sonication process, either prior to or following sonication. Pretreatment with ultrasound illustrated a more profound effect on barley starch than sequential germination and ultrasound treatment. In conclusion, these results indicate that sequential ultrasound pretreatment and germination improve the fine structure of highland barley starch.

A microbotanical and microwear perspective to plant processing activities and foodways at Neolithic Çatalhöyük

Çatalhöyük is a renowned archaeological site in central Anatolia, best known for its Neolithic occupation dated from 7100 to 6000 cal BC. The site received worldwide attention early on for its large size, well-preserved mudbrick architecture, and elaborate wall paintings. Excavations at the site over almost three decades have unearthed rich archaeobotanical remains and a diverse ground stone assemblage produced by what once was a vibrant farming community. The study presented here adds to our understanding of crops and plant processing at Çatalhöyük by integrating phytoliths and starch analyses on grinding implements found at three domestic contexts attributed to the Middle (6700-6500 cal BC) and Late (6500-6300 cal BC) period of occupation. Our results reveal a rich microbotanical assemblage that testifies the use of a wide range of geophytes and wild seasonal resources previously unknown at the site. Moreover, by comparing results from the microbotanical proxies and microscopic wear patterns on artefacts, we are also able to discern various plant processing practices the analysed artefacts were employed for. In sum, this work further expands our understanding of plants and crop processing activities performed by the inhabitants of Neolithic Çatalhöyük.

Analyzing the effect of germination on the pasting, rheological, morphological and in- vitro antioxidant characteristics of kodo millet flour and extracts

The present investigationwas carried out to determine the effect of germination on pasting, rheological, morphological properties of Kodo millet flour and in-vitroantioxidant characteristics of its phenolic and γ-amino butyric acid extracts. Rheological analysis depicted complex flour viscosity decreased with an improvement in shear intensity, symbolizing the shear-thinning action of flour upon germination. The frequency and temperature sweep demonstrated a decrease in visco-elasticity as a result of germination wherein, SEM revealed destruction in the continuous composite structure of starch which got entangled in dense protein matrix following germination. The in-vitroantioxidant activities such as total antioxidant capacity, DPPH*, FRAP, metal chelating ability and hydrogen peroxide scavenging activities of both the extracts increased significantly. There was a decrease in pasting properties and gelatinization behaviour whereas, visco-elastic solid behaviour changed to visco-elastic fluid. This research explores the potential of germinated Kodo millet flour for valuable bioactive compounds extraction and its utilization in product development.

Effect of malting and fermentation on colour, thermal properties, functional groups and crystallinity level of flours from pearl millet (Pennisetum glaucum) and sorghum (Sorghum bicolor)

The effect of malting and fermentation on colour, thermal properties, level of crystallinity and functional groups of Agrigreen, Babala pearl millet cultivars and sorghum flours were studied using response surface methodology. The central composite rotatable design was performed on two independent variables in terms of malting and fermentation time at intervals of 24, 48 and 72 h, respectively using design expert software. One-way analysis of variance at p < 0.05, regression analysis, response surface plots for interactions between malting and fermentation processing times with response variables were recorded. The results indicated that malting and fermentation times have significant effects on the thermal and colour properties as well as the level of crystallinity and functional groups of pearl millet cultivars and sorghum flours. In terms of colour, sorghum exhibited high content in L∗ at 72.02-73.72, a∗ ranged from 2.50-3.30 and chrome at 13.10-14.82, while Babala flour was high in b∗ and hue at 12.15-14.27 and 73.00-84.80, respectively. In terms of thermal properties, sorghum was noticed to be high in melting peak at 87.57-104.83 °C, 102.66-111.14 °C for end completion and gelatinisation range at 10.70-25.79 °C, whereas, Babala recorded high values in onset and enthalpy at 93.20-100.11 and 5.72-21.62 J/g, respectively. The Fourier transform infrared (FTIR) spectroscopy showed that malted and fermented Agrigreen, Babala and sorghum flour showed peaks in OH, carbonyl, amide and C-O bonding. The optimal processing time for the colour of Agrigreen was 50.69 h (malting) and 39.38 h (fermentation), Babala was 54.40 h (malting) and 65.30 h (fermentation); and sorghum was 49.90 h (malting) and 54.61 h (fermentation). While the optimal malting and fermentation time for thermal properties for Agrigreen was 45.78 h and 42.60 h; Babala was 40.94 h and 29.07 h and sorghum was 34.83 h and 36.33 h, respectively with product quality at the desirability of 1.00. X-ray diffractogram results of the optimum processing points of the thermal properties showed that malted and fermented Agrigreen, Babala and sorghum flour showed high peak intensities, while the unprocessed flour exhibited diffused peaks. The obtained results would assist food processing companies to improve the colour and thermal properties and also the behaviour of the crystallinity and functional groups in food during processing.

Effect of germination duration on structural and physicochemical properties of mung bean starch

Mung bean seeds were germinated at 25 °C for 12, 24, 36, 48, 60 and 72 h. Changes in structural and physicochemical properties of mung bean starch during germination were investigated. Microscopy analysis showed germination did not change the shape of starch granules, but granules isolated from germinated mung bean starch exhibited dents surface structure compared with smooth surface of native starch. The molecular weight of starch isolated from germinated mung bean was found to be smaller than that of native ones. Although germinated mung bean showed greater crystallinity than that of native sample, the germination did not change the crystalline structure type of starch (C-type). Moreover, solubility and swelling power of starch varied depending on germination duration and testing temperature. Peak viscosity and trough viscosity slightly decreased as germination prolonged to 72 h. Furthermore, starch isolated from mung bean germinated for 12 h showed greater enthalpy (ΔH) than that of starch isolated from native sample; while, ΔH decrease as germination time prolonged from 36 to 72 h. The obtained results may help in understanding the influence of germination on functional properties of mung bean starch and choosing appropriate applications to promote utilization of mung bean starch in food industry.

Cooking Characteristics and Sensory Evaluation of Rice Cooked with Germinated Barley

This study was performed to investigate the cooking characteristics and sensory evaluation of rice cooked in the presence of 20 % germinated barley. The soluble solid and water absorption rate increased significantly with longer barley germination periods. The microstructure of the cooked germinated barley showed some pores 4 days after germination and increased pore numbers and size 6 days after germination. The hardness of cooked-rice tended to decrease after germination of barley. Sensory evaluation indicated that barley germinated for 2–4 days is the most suitable (overall acceptance) for cooking. These results indicate that pores are formed on the surface during the germination of barley, so that water is easily absorbed during cooking and the hardness is low, and the texture of barley is improved even when rice is cooked. This study suggests that rice cooked with germinated barley has improved sensory characteristics, without unnecessary processing (milling, chopping, or pressing) the barley.

A novel starch: Characterizations of starches separated from tea (Camellia sinensis (L.) O. Ktze) seed

The physicochemical, thermal and crystal properties of starches isolated from 3 different tea (Camellia sinensis (L.) O. Ktze) seeds were analyzed in this study. The shape of tea starch granules were flat spherical or oval shape, showed unimodal or bimodal distribution with average size of around 9 μm. Tea starch was typical A-type starch. Apparent amylose contents of three tea seed starches ranged from 27.06% to 33.17%. The chains having degree of polymerization (DP) 13-24 were over 50% of the total detectable chains for tea amylopectin. Peak gelatinization temperature of tea starch ranged from 65 to 77 °C and the water solubility reached up to 9.70%. The peak viscosity of tea starches were as high as 5300 cP and final viscosity ranged from 4000 to 6700 cP. The results indicated that tea seed starch had potential as gel reagents and provide some guides for comprehensive utilization of tea starch in food and non-food applications.

Comparison of pasting properties measured from the whole grain flour and extracted starch in barley (Hordeum vulgare L.)

Pasting properties of barley starch are important characteristics from a processing standpoint. The isolation of starch form barley grains is time consuming thus the whole grain flour is always used. To compare pasting properties of starch with those of the whole grain flour, we used a Rapid Visco Analyser (RVA) to measure pasting properties of three types of samples: grain flour and starches isolated using two different extraction methods. We also investigated compositional, morphological and structural properties of the two starch samples. Significant differences in pasting properties were found among the three sample types, but most of the parameters of pasting properties displayed significant correlations between flour and starch. No significant differences were found in amylose/amylopectin ratio, granule morphology, granule size distribution and crystal structure between starches extracted using two different methods. However, the starch isolated from water homogenization had a higher protein content and lower total starch, amylose and amylopectin contents than the starch extracted with homogenized extraction under alkaline conditions. We concluded that the whole grain flour can be used to predict the pasting properties in breeding programs.

Bioactive components and functional properties of biologically activated cereal grains: A bibliographic review

Whole grains provide energy, nutrients, fibers, and bioactive compounds that may synergistically contribute to their protective effects. A wide range of these compounds is affected by germination. While some compounds, such as β-glucans are degraded, others, like antioxidants and total phenolics are increased by means of biological activation of grains. The water and oil absorption capacity as well as emulsion and foaming capacity of biologically activated grains are also improved. Application of biological activation of grains is of emerging interest, which may significantly enhance the nutritional, functional, and bioactive content of grains, as well as improve palatability of grain foods in a natural way. Therefore, biological activation of cereals can be a way to produce food grains enriched with health-promoting compounds and enhanced functional attributes.

Malting and fermentation effects on antinutritional components and functional characteristics of sorghum flour

The research was aimed to observe the effect of malting and fermentation on antinutritional component and functional characteristics of sorghum flour. For whole sorghum flour, cleaned sorghum grain was milled to pass through 40 mesh sieve. For malting, cleaned sorghum grain was steeped in 0.2% calcium hydroxide solution for 24 hr and then germinated for 48 hr at 90% RH and 27 ± 2°C. Sprout was removed, dried in hot air oven at 50 ± 2°C for 24 hr and milled to pass through 40 mesh sieve. For fermented sorghum flour, 13.3 mg% diastase and 2 mg % pepsin (on the basis of whole sorghum flour weight) was added to cooked (88 ± 2°C) sorghum flour and left for 1 hr. Lactobacillus plantarum (107 cfu/g) was inoculated and incubated at temperature 30 ± 2°C for 48 hr. The fermented slurry was dried at 50 ± 2°C in hot air oven for 24 hr and milled to pass through 40 mesh sieve. The lower yield of sorghum flour was obtained compared to whole and malted sorghum flour. Germination of sorghum reduced phytate, tannin, and oxalate by 40%, 16.12% and 49.1%, respectively, whereas fermentation of sorghum flour reduced above by 77%, 96.7% and 67.85%, respectively. There was no significant change in hydrogen cyanide in malted sorghum flour compared to whole sorghum flour, but fermentation of sorghum flour reduced hydrogen cyanide by 52.3%. Bulk density and viscosity was significantly reduced by the malting and fermentation, whereas water absorption capacity and oil absorption capacity was markedly increased by the malting and fermentation. Fermented flour was good due to reduced ANF and improved functional property despite of lower yield.

Influence of steeping duration, drying temperature, and duration on the chemical composition of sorghum starch

The quest for high-quality starch that would meet the needs of manufacturers is ever increasing. This study investigated the effect of steeping duration, drying temperature, and duration on the chemical properties of sorghum starch, to possibly alter the characteristics of sorghum starch for food applications. Steeping duration, drying temperature, and drying time of starch isolation were optimized using a central composite design and nine parameters including pH, amylose content, moisture, protein, ash, crude fiber, fat, carbohydrate, and total energy determined. Results obtained showed that most of the parameters were majorly influenced by steeping and drying duration. Steeping duration significantly (p < .05) increased the moisture, protein, and ash content of the sorghum with a corresponding decrease in pH values. The obtained experimental and predicted values of the investigated parameters were similar, with statistical indices indicating the relative validity of the generated models [absolute average deviation (AAD between 0 and 0.20), bias factor (B_f , 1-1.02), and accuracy factor (A_f , 1-1.21)]. The varying values of the parameters obtained indicates the potential use of the sorghum starches as thickeners, starch substitutes, and for other desired roles in food processing.

Changes in nutritional and physico-chemical properties of pearl millet (Pennisetum glaucum) Ex-Borno variety flour as a result of malting

The effect of malting periods on the nutritional composition and physico-chemical properties of flour from pearl millet (Ex-Borno) variety was evaluated. Grains were steeped at 25 °C for 24 h and germinated for different durations (12, 24, 36, 48, 60, 72, 84 and 96 h) before kilning at 55 °C for 18 h. The kilned seeds were devegetated, milled, sieved and analysed for their proximate composition, amino acid composition, total phenolic content, functional and pasting properties. The carbohydrate, fat and total phenolic contents of the pearl millet flour samples decreased while protein content increased with increased malting periods. Leucine was the dominant amino acid in the flour and 48 h-malted flour had the highest total amino acid (6.72). Peak viscosity significantly decreased as the malting period increased. Solubility index, pasting temperature and phenolic content of the flours ranged from 5.13 to 17.24%, 69.05 to 89.5 °C and 130.20 to 169.90 mg/100 g, respectively. Malting offers a means of improving the nutritional profile of Ex-Borno pearl millet flour with an increased protein and fibre and reduced fat content. Malting also enhanced the functional and pasting properties of the flour.

Physicochemical properties of sorghum flour are selectively modified by combined germination-fermentation

The combined effects of grain germination and of subsequent fermentation on the physicochemical properties of sorghum flour were investigated by studying the structural changes occurring in the starch and protein fractions and by assessing their effects on physical properties of the resulting materials most relevant to end use. The sequential treatments were more effective than either individual treatment in the modification of starch-related properties, whereas modification of the protein components only occurs in the fermentation step, almost regardless of a previous germination step. The resulting profile of physicochemical traits offers several hints as for the suitability of flour from treated sorghum as an ingredient for various types of gluten-free food products, and provides a basis for expanding the use of processed sorghum in applications other than traditional African foods.

Exploiting Nutritional Value of Staple Foods in the World's Semi-Arid Areas: Risks, Benefits, Challenges and Opportunities of Sorghum

Sorghum (Sorghum bicolor (L.) Moench) is a drought-resistant crop and an important food resource in terms of nutritional as well as social-economic values, especially in semi-arid environments. Cultivar selection and processing methods have been observed to impact on composition and functional and nutritional value of sorghum. Amino acid imbalance, cyanogenic glycosides, endogenous anti-nutrients, mycotoxins and toxic elements are among factors impairing its nutritional value. This paper reviews possible approaches (varieties selection, production practices, cooking processes) to improve the benefits-to-risks balance of sorghum meal, to mitigate the risk of deficiencies and/or imbalances and to improve effects on human nutrition. Opportunity for avoiding dietary diversification in high sorghum consumers is also discussed, e.g., tryptophan and niacin deficits potentially related to pellagra, or unavailability of proteins and divalent cations (e.g., Fe, Zn) due to the antinutrient activity of phytic acid and tannins. As potential candidate for production investments, the role of sorghum in preserving biological diversity is also considered.

Development and standardization of sorghum pasta using extrusion technology

Extrusion cooking is a unique method for preparing pasta, which is generally produced from durum wheat semolina. However, preparation of pasta from sorghum is not practiced in India. Therefore, the present study was undertaken to develop and standardize pasta from sorghum cultivar, M35-1 and wheat semolina of 0.1 mm particle size. Sorghum and wheat semolina in different proportions (T1;S:W-50:50,T2;S:W-60:40,T3;S:W-70:30,T4; S:W-80:20, T5; S -100) were mixed with lukewarm water (40 °C) in the cold extruder for 30 min and passed through the extruder with a screw speed of 80 rpm and at a temperature of 55° to obtain pasta of diameter (0.6 mm) and length (1.4 mm). The extruded pasta was dried at 70 °C in a tray drier for 8 h, cooled and stored in polyethylene bags at room temperature. The pasta was subjected to physico-chemical analysis such as length, diameter, bulk density, water absorption, cooking time, cooking loss, moisture, water activity, alcoholic acidity, amylase, carbohydrates, fat, protein, fibre and ash using standard methods. Organoleptic characteristics such as color and appearance, texture, taste, flavor and overall acceptability, stickiness, bulkiness and firmness were evaluated at laboratory level by a panel of semi trained judges using 5 point hedonic rating scale. Among the various blends studied, the sorghum and wheat semolina with a combination of 50:50 (T1) and 60:40 (T2) and 70:30 (T3) were more acceptable than others. Well acceptable sorghum pasta can be developed from sorghum and wheat, thereby improving its nutritional composition.

Some physicochemical properties of flour from germinated sorghum grain

A Sudanese sorghum cultivar (Fetarita) was germinated for 3 days. Stability and clarity of sorghum pastes, freeze-thaw stability, gel consistency, and swelling power were measured every 24 h. There is no substantial difference in stability and clarity between flour samples from germinated and ungerminated sorghum, but a different behavior was observed between samples stored at room temperature and at 4 °C. Cooked paste derived from germinated sorghum flour presented higher syneresis than that derived from ungerminated sorghum flour over the first three cycles but when the cycle number increased, both flours showed zero syneresis value. For the gel consistency the flours derived from germinated sorghum produced thinnest gels. The neutral and acid gel consistency increased when the germination time increased. Germination had not much effect on the swelling power of sorghum flour.