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1.
Ozone has been reported as being able to degrade macromolecules such as cellulose, starch, lignins, and tannins in the textile, pulping, and water‐treatment industries. Thus, we hypothesized that ozone treatment may also inactivate tannin activity and increase fermentation efficiency of tannin sorghum lines. The objective of this research was to study the physicochemical properties of ozone‐treated whole tannin grain sorghum flour and its fermentation performance in ethanol production. Results showed that the ethanol yields from ozone‐treated tannin grain sorghums were significantly higher than yields from the untreated flour. The fermentation efficiency of ozone‐treated tannin grain sorghum was approximately 90%, which was 8–14% higher than that of untreated samples at the 36th hr of fermentation. At the end of 72 hr of fermentation, the efficiencies of ozone‐treated sorghum flour were 2–5% higher than those of untreated samples. Measured tannin levels of ozone‐treated samples decreased significantly from 3.8 to 2.7%. Gel‐permeation chromatographic results indicated that both degradation and polymerization processes might have happened to starch molecules during ozone treatment. Rapid Visco Analyzer data showed that the setback of viscosity of ozone‐treated flour was lower than that of untreated flours. Distillers dried grains with solubles made from ozone‐treated sorghum were low in residual starch (<1%) and high in crude protein (≈35%). Therefore, ozonation could be a novel and useful method to improve ethanol yield and fermentation efficiency of tannin grain sorghum.  相似文献   

2.
Brans of specialty sorghum varieties (high tannin, black, and black with tannin) were used to investigate the effects of sorghum phenolic compounds on starch digestibility of soft and hard sorghum endosperm porridges. Endosperms of varieties with the highest and lowest grain hardness index were mixed with brans of specialty sorghum varieties in the ratio of 85:15 and cooked into porridges with distilled water using a Rapid Visco Analyzer. Brans of condensed tannin containing sorghum varieties (high‐tannin and black with tannin sorghums) significantly (P < 0.05) decreased starch digestibility and estimated glycemic index (EGI) and increased resistant starch (RS) content of endosperm porridges. However, the addition of phenolic‐rich tannin‐free (mostly anthocyanins) black sorghum bran significantly (P < 0.05) increased starch digestibility and EGI but did not affect RS content of endosperm porridges. The disparate effects with black bran may, in part, result from its larger particle size and different bran structure compared with other sorghum varieties evaluated. Thus, our study showed that not only presence of phenolic compounds in the brans but also structural differences of specialty sorghum brans can have significant effects on starch digestibility.  相似文献   

3.
Grain hardness affects sorghum and maize processing properties especially for dry milling. A variety of simple grain quality parameters were assessed on 17 sorghum and 35 white maize hybrid cultivars grown in six and four locations, respectively, in South Africa. The purpose was to determine tests that can be used to distinguish hardness in commercial sorghum and maize. The grains were characterized by test weight (TW), thousand kernel weight (TKW), decortication with the tangential abrasive dehulling device (TADD), and kernel size. Maize was also characterized for susceptibility to breakage, stress cracking, and near‐infrared transmittance (NIT) milling index. Principal component analysis showed that, in nontannin and tannin sorghums, TADD hardness and TW were closely correlated (P < 0.001). In maize, TADD hardness was closely correlated (P < 0.001) with NIT milling index and TW. Hence, TADD hardness and NIT milling index or TADD hardness and TW would be suitable for maize hardness evaluation. A combination of TADD hardness, TW, TKW, and kernel size >3.35 mm can be used together to select sorghum grain for hardness. It thus appears that TADD hardness is an excellent method of estimating both sorghum and maize hardness that can be applied for routine batch analysis and cultivar evaluation.  相似文献   

4.
A high‐tannin sorghum cultivar with 3.96% tannin content was used to study the effects of germination on its ethanol fermentation performance in a laboratory dry‐grind process. High‐tannin sorghum sample was germinated for 3 and 4 days. Original and germinated samples were analyzed for tannin, starch, protein, free amino nitrogen (FAN), and glucose content. Endosperm structures and flour pasting properties of germinated and nongerminated sorghum samples were examined using a scanning electron microscope (SEM) and rapid visco analyzer (RVA). Germination reduced tannin content from 3.96% to negligible levels. The free fermentable sugars (glucose, maltose, and maltotriose) in the germinated samples were significantly higher than those in the nongerminated control. Judged by the starch (starch plus dextrin) and free amino nitrogen contents in the mashed samples, germination improved degree of hydrolysis for starch by 13–20% and for protein by 5‐ to 10‐fold during mashing. Germination significantly shortened the required fermentation time for ethanol production by 24–36 hr, increased ethanol fermentation efficiency by 2.6–4.0%, and reduced the residual starch content in the distillers dried grain with solubles (DDGS) compared to the nongerminated control. Ethanol yield for the 3‐day germinated samples was 2.75 gallons/bushel, which was 3.1% higher than the 2.67 gallons for the nongerminated control. Ethanol yield for the 4‐day germinated sorghum was 2.63 gallons/bushel due to excessive loss of starch during germination.  相似文献   

5.
Chemical treatments in wet milling could improve the physico‐chemical properties of starch isolated from high‐tannin sorghums. Sorghums Chirimaugute (medium‐tannin), DC‐75 (high‐tannin), and SV2 (tannin‐free) were steeped in water, dilute HCl (0.9%, v/v), formaldehyde (0.05%, v/v), and NaOH (0.3%, w/v) solutions before wet milling and starch separation. Pasting, textural, and thermal properties of starch were determined. Steeping in NaOH resulted in starches with higher peak viscosity (PV), cool paste viscosity (CPV), and setback than when water, HCl, and formaldehyde were used. The time to PV (Ptime) and PV temperature (Ptemp) were markedly reduced by treatment with NaOH. NaOH could have caused a degree of pregelatinization. HCl treatment gave starches with higher Ptemp and P time, presumably due to delayed granule swelling. Gel hardness was largely determined by the starch amylase content. The low hardness of DC‐75 starch gels was slightly improved in NaOH‐treated grains. Gelatinization temperatures of sorghum starches were generally low, regardless of steeping treatment. Starch from NaOH‐treated grain generally had slightly higher gelatinization temperatures than when water, HCl, or HCHO was used. Chemical treatments during steeping of sorghum grains greatly affected starch properties. Dilute alkali steeping during wet milling could be used to improve properties of starch isolated from tannin‐containing sorghums.  相似文献   

6.
Starch was isolated from 95 sorghum landraces from Zimbabwe using an alkali steep and wet‐milling procedure. The physicochemical properties of sorghum starch were examined for potential use in Southern Africa. All the landraces evaluated had a normal endosperm indicated by the amylose content of the starches. Starch properties were not correlated to most of the physical grain quality traits evaluated. Grain hardness was weakly correlated to starch gel adhesiveness (r = 0.36) and amylose content (r = 0.38) (P < 0.001). The mean peak viscosity (PV) of the sorghum starches was 324 Rapid Visco Analyser units (RVU) compared with 238 RVU in a commercial corn starch sample; PV was 244–377 RVU. Some landraces had low shear‐thinning starches, implying good paste stability under hot conditions. Pasting properties were highly correlated among the sorghum starches. The starch gel hardness showed considerable variation (44–71 g) among the landraces. Gelatinization peak temperatures were 66–70°C. The thermal properties of starches were not correlated with starch swelling and pasting properties. Genotype grouping by highest and lowest values in each category would allow selection of sorghums based on a specific attribute depending on the desired end use.  相似文献   

7.
Cookies were produced from different sorghum flours to determine their potential as vectors of antioxidants. Different sorghum cultivars and their flour extraction rates were evaluated for their effects on phenolic content and antioxidant activity of the cookies. Consumer acceptance of the sorghum cookies was compared with that of wheat flour cookies. For each sorghum cultivar, cookies of 100% extraction rate flours had two to three times more total phenolics compared with those of 70% extraction rate flours, while antioxidant activity was 22–90% higher. Cookies of the condensed tannin sorghum had two to five times more phenolics compared with those of condensed tannin‐free sorghum. Antioxidant activity was 145–227 μMol Trolox equivalents (TE)/g in cookies of condensed tannin sorghum compared with 10–102 μMol TE/g in those of condensed tannin‐free sorghum. The sorghum flours had slightly higher phenolic content and antioxidant activity values than their corresponding cookies. Cookies of the red tannin‐free sorghum flours (PAN 8564/8446) were equally liked as wheat flour cookies, except for texture. However, cookies of condensed tannin sorghum were least accepted compared with wheat flour cookies despite their high antioxidant activity.  相似文献   

8.
A method of comparing milling values of sorghum by adjusting yields to standard L values was developed. The milling values of ‘Dorado’ (an excellent food-type sorghum variety), ‘ATx399 × RTx430’ (a commercial red sorghum hybrid) and three ‘Warner 902W’ (commercial white food type hybrids with different levels of weathering designated W-1, W-2, and W-3) were determined using a tangential abrasive dehulling device for various times. Color (L, a, b) was measured on the decorticated grain (grits) and the ground grits (flour). The yields (by weight) of flours adjusted to an L value of 85 were 93, 88, 86, 84, and 70% for Dorado, W-2, W-1, W-3, and red, respectively. The b (yellow) values were highest for red and lowest for Dorado. The grits yields were 96, 89, 84.5, 81.5, and 56.5% when adjusted to an L of 67 for Dorado, W-2, W-1, W-3, and red sorghums, respectively. Milling yields expressed at comparable flour or grit color clearly demonstrate that white food-type sorghums have significantly better milling yields than red sorghums. Adjusting milling yields to a standard L value is an accurate and easy way to compare milling properties of sorghums for yield and product color.  相似文献   

9.
Development of high‐protein digestibility (HPD)/high‐lysine (hl) sorghum mutant germplasm with good grain quality (i.e., hard endosperm texture) has been a major research objective at Purdue University. Progress toward achieving this objective, however, has been slow due to challenges posed by a combination of genetic and environmental factors. In this article, we report on the identification of a sorghum grain phenotype with a unique modified endosperm texture that has near‐normal hardness and possesses superior nutritional quality traits of high digestibility and enhanced lysine content. These modified endosperm lines were identified among F6 families developed from crosses between hard endosperm, normal nutritional quality sorghum lines, and improved HPD/hl sorghum mutant P721Q‐derived lines. A novel vitreous endosperm formation originated in the central portion of the kernel endosperm with opaque portions appearing both centrally and peripherally surrounding the vitreous portion. Kernels exhibiting modification showed a range of vitreous content from a slight interior section to one that filled out to the kernel periphery. Microstructure of the vitreous endosperm fraction was dramatically different from that of vitreous normal kernels in sorghum and in other cereals, in that polygonal starch granules were densely packed but without the typically associated continuous protein matrix. We speculate that, due to the lack of protein matrix, such vitreous endosperm may have more available starch for animal nutrition, and possibly have improved wet‐milling and dry‐grind ethanol processing properties. The new modified endosperm selections produce a range that approaches the density of the vitreous parent, and have lysine content and protein digestibility comparable to the HPD/hl opaque mutant parent.  相似文献   

10.
The objective of this research was to investigate the fermentation performance of waxy grain sorghum for ethanol production. Twenty‐five waxy grain sorghum varieties were evaluated with a laboratory dry‐grind procedure. Total starch and amylose contents were measured following colorimetric procedures. Total starch and amylose contents ranged from 65.4 to 76.3% and from 5.5 to 7.3%, respectively. Fermentation efficiencies were in the range of 86.0–92.2%, corresponding to ethanol yields of 2.61–3.03 gallons/bushel. The advantages of using waxy sorghums for ethanol production include easier gelatinization and low viscosity during liquefaction, higher starch and protein digestibility, higher free amino nitrogen (FAN) content, and shorter fermentation times. The results showed a strong linear relationship between FAN content and fermentation rate. Fermentation rate increased as FAN content increased, especially during the first 30 hr of fermentation (R2 = 0.90). Total starch content in distillers dried grains with solubles (DDGS) was less than 1% for all waxy varieties.  相似文献   

11.
Some physicochemical properties and molecular structures of starches from millet (Pennisetum typhoides, Doro and Gero) and sorghum (Sorghum bicolor, red and white) in Nigeria were examined. Starch granules of millet and sorghum were 3–14 μm and 4–26 μm in diameter, respectively. Millet cultivars had similar peak viscosities (204–205 RVU) on pasting, while sorghum showed similar minimum viscosities (155–156 RVU). The actual amylose content (%) calculated from iodine affinity (IA, g/100 g) was 20.1 and 21.4 for sorghum and 21.3 for millet. The IA of amylopectin was high (1.27–1.42) and its average chain lengths were 20–21 with β‐amylolysis limit of 56%. Amylopectins showed a polymodal molecular weight distribution on a molar basis. The distributions differed among the samples with a higher amount of larger molecules in Doro and red sorghum. Weight‐ and molar‐based distributions of debranched amylopectins on HPSEC were polymodal with weight‐based distribution showing presence of long chains. Peak DP values for A+B1 and B2+B3 chain fractions were 13–16 and 42–43, respectively. The (A+B1)/(B2+B3) ratio on molar basis (9.0–11.5) was similar to maize and rice amylopectins. Peak DP on molar‐based distribution for white sorghum and millet amyloses were similar (490–540) and the DPn range was narrow (1,060–1,300), but weight‐based distribution profiles differed. The average chain lengths were 260–270 with 3.9–4.8 chains per molecule.  相似文献   

12.
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13.
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14.
Proteolysis during cereal germination is vital both to seedling growth and the success of commercial malting and brewing. In this study, proteinases in proteolytic extracts from seeds and germinated grains of 11 Botswana sorghum cultivars were analyzed and partially characterized by one‐dimensional electrophoresis on SDS‐PAGE gels containing incorporated gelatin. Proteinase polymorphism was detected in both germinated and ungerminated sorghum grains. Fifteen distinct proteinase bands, with Mr values of 27,000–100,000 were detected in sorghum malt extract, while ungerminated sorghum displayed a maximum of four bands (Mr ≈ 78,000–100,000). Band numbers and identity varied markedly according to cultivar. More proteinase bands were detected at pH 4.6, than at pH 6.2 and 7.0, suggesting pH optima considerably below neutrality. Cysteine‐proteinases constituted a higher proportion (9 of 15) of the detected sorghum malt proteinases and were most detectable at pH 4.6. Multiple representatives were also detected for both serine‐ and metallo‐proteinases, although these were more active at pH 6.2 and 7.0. 1‐10 Phenanthroline inhibited malt metallo‐proteinase more strongly than EDTA, suggesting that these enzymes were most probably zinc‐dependent. Aspartyl‐proteinases were not detected, probably because of the substrate employed. Results indicate that the sorghum proteinase system is complex.  相似文献   

15.
Commercial and food-type sorghum hybrids with differing kernel and endosperm characteristics were grown under comparable conditions and steam flaked in each of three years. The raw-grain kernel characteristics and proximate analyses were homogenous over the three-year period. The waxy hybrid produced large, translucent, durable flakes that had significantly higher enzyme-susceptible starch values for all years compared to the other varieties. Flakes with lower amylose contents (waxy endosperm) were positively correlated with percent whole flakes (r2 = 0.509), flake diameter (r2 = 0.846), and enzyme-susceptible starches (r2 = 0.564) and negatively correlated with higher flake fragility (r2 = -0.647), test weight (r2 = -0.626), and flake breakage (r2 = -0.560). The heterowaxy flakes had a good appearance and were generally comparable in quality to the nonwaxy commercial and experimental hybrids. Heterowaxy sorghum hybrids with good grain yields can provide improved quality grain and flakes without sacrificing agronomic performance and yields. No difference in flaking performance was detectable among the kernels with different pericarp colors; flakes from the white food-type sorghums had excellent appearance. Nontempered control samples were inferior in quality to all conditioned treatments.  相似文献   

16.
In this study, it was verified whether silicon (Si) affected plant hydraulic resistance, which was one of the significant factors affecting water uptake. Sorghum bicolor (L.) Moench. was grown hydroponically under varying silicon levels and exposed to osmotic stresses. Under osmotic stress, reduction in growth, photosynthesis, and transpiration were alleviated as supplied silicon levels increased. These alleviative effects were ascribed to enhancement of water uptake. Although shoot/root ratio was not affected by silicon, estimated apparent hydraulic resistance was lower in silicon-supplied sorghum than silicon-deficient one under osmotic stress. Simultaneous measurement of transpiration and water uptake rates indicated that under osmotic stress silicon-deficient sorghums showed unbalanced water relation that transpiration rate exceeded water uptake rate, while they were balanced in silicon-supplied sorghums. The results indicated that silicon improved hydraulic resistance, allowing sorghum to avoid from decrease in water uptake rate that happens to silicon-deficient sorghum under water stress.  相似文献   

17.
A small‐scale (100 g of grain) procedure was developed to wet‐mill grain sorghum into six fractions by modifying the procedure of Eckhoff et al (1996). The wet‐milling process was repeated five times on commercial grain sorghum, and the mean yield (69.4%) of starch (≤0.3% protein) varied by 0.3%, whereas the yields of fiber, gluten, and germ plus bran fractions varied by 5–6%. The starch fraction accounted for ≈95% of that in the grain, while the total solids recovered was 99.0%. Four other samples of grain sorghum gave 92–95% recoveries of starches and 98.2–99.8% recoveries of total solids. All grain sorghum starches had lightness (L*) values and pasting curves nearly equal to those of a commercial maize starch.  相似文献   

18.
Grain sorghum has been documented to have low protein digestibility relative to other cereal grains. Low protein digestibility of sorghum is most pronounced in cooked foods and is ranked slightly lower than corn as a feed grain. In this article, sorghum germ plasm is identified that has substantially higher uncooked and cooked flour in vitro protein digestibility than normal cultivars. Sorghum lines were found within a high-lysine opulation derived from the mutant P721Q that have ≈10–15% higher uncooked and ≈25% higher cooked protein digestibilities using a pepsin assay. Highly digestible sorghum grain showed little reduction in digestibility after cooking, compared to the large reduction that is typical of normal sorghum cultivars. Using the three-enzyme pH-stat method, we showed that the highly digestible lines had the same degree of peptide bond hydrolysis in ≈5 min, as was found in 60 min in the normal cultivar, P721N. Differences in protein digestibility were related to enyzme susceptibility of the major storage prolamin, α-kafirin, that comprises ≈50–60% of the total sorghum grain protein. Using the enzyme-linked immunosorbent assay (ELISA) technique to track the pepsin digestion of α-kafirin, the highly digestible lines had ≈90–95% α-kafirin digested in 60 min compared to 45–60% for two normal cultivars. γ-Kafirin, a minor structural prolamin found mainly at the periphery of protein bodies, was also somewhat more digestible in the highly digestible sorghums. Highly digestible grain was of a floury kernel type, though recently this trait has been found in a modified background. More digestible protein from sorghum grain, that additionally is high in lysine content and has a fairly hard endosperm, could be of important benefit to populations who lack adequate protein in their diets, and may, pending further studies, prove to increase the value of sorghum as a feed grain.  相似文献   

19.
Sorghum bran, a coproduct of sorghum dry milling, could be a source of protein for industrial applications. Condensed tannin‐free red and white sorghum samples were decorticated by abrasion until ≈10 or 25% grain by weight was removed. Kafirin was then extracted from the milling fractions using an aqueous ethanol based solvent system. The brans were darker and considerably higher in protein and fat compared with the whole grain flours and decorticated grain flours, with the 25% bran having higher protein than the 10% bran. This is due to increased contamination of the bran with protein‐dense, corneous endosperm. The protein extracted from all the milling fractions, including the brans, was pure kafirin. However, the yield of kafirin from the brans (15.9–26.7% of total protein present) was somewhat lower than that from whole grain and decorticated grain flours (45.0–57.9% of total protein present), due to the fact that kafirin is located solely in the endosperm. Also, the kafirin from bran was more contaminated with fat, polyphenols, and other substances, and more highly colored, particularly the kafirin from red sorghum. Thus, sorghum bran could be used as a source of kafirin but further purification steps may be necessary.  相似文献   

20.
Nitrogen uptake and nitrate-N concentration in forage sorghums, which are related to ground water pollution or feed quality under conditions of crop fertilization by only animal wastes, were examined. Seventy-four genotypes of sorghum and Sudan grass were tested. They were classified into 4 groups; grain type and dual purpose type sorghums (6 and 13 genotypes, respectively, Sorghum bicolor Moench), sorgo type sorghum (21, S. bicolor), Sudan type sorghum (22, S. bicolor × S. sudanense (Piper) Stapf), Sudan grass (12, S. sudanense). There was a strong correlation between dry matter (DM) yield and N uptake, with the sorgo type producing the highest DM matter yield and showing the highest N uptake. Nitrate-N, which causes nitrate poisoning of ruminants, was detected mostly in the stem of all the genotypes. The nitrate-N concentration based on DM could be calculated accurately by multiplying the nitrate-N concentration of stem on a fresh matter basis by the DM partitioning ratio of stem divided by the DM concentration of stem. The grain type and the dual purpose type of sorghums with dry stem showed the lowest nitrate-N concentration because these plants had a lower DM partitioning ratio of stem and higher DM concentration of stem. Sudan grass and Sudan type sorghum with the genetic background of Sudan grass showed higher nitrate-N concentrations owing to their ability to accumulate nitrate-N.  相似文献   

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