Extraction, determination and fractionation of sorghum polyphenols

Youssef, Abou-Bakr M.; Bolling, H.; Moustafa, E.K.; Moharram, Y. G.

doi:10.1016/0308-8146(88)90148-3

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…The total phenol content of the sorghum bran was four times that of the sorghum whole grain. This is because phenols are mainly located in the pericarp (bran) of the sorghum caryopsis 20, 22. Aqueous acetone was generally a more efficient extraction solvent of total phenols in sorghum bran than water (bran infusions).…”

Section: Resultsmentioning

confidence: 99%

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Effects of phenolics in sorghum grain on its bitterness, astringency and other sensory properties

2007

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Despite the fact that condensed tannins are potentially important antioxidants, there is a general belief that tannins in sorghum confer objectionable sensory attributes. The objective of this study was to determine differences in the sensory attributes of sorghums containing different levels of total phenolic compounds. A trained sensory panel described and quantified the sensory attributes of different sorghums (condensed-tannin containing and tannin-free). All the sorghum cultivars were perceived as bitter and astringent. Bran infusions of tannin sorghums were perceived as darker, clearer, more bitter and more astringent than those of the tannin-free sorghums, while those of tannin-free sorghums were perceived as sweeter and cloudy. Sorghum whole-grain rice from the tannin sorghums which had relatively soft endosperm texture (PAN 3860 and Ex Nola 97 GH) was perceived as dark, hard, chewy, bitter and astringent, while that from tannin-free sorghums having relatively hard endosperm texture (Segaolane and Phofu) was perceived as soft, sweet and had a maize-flavour. Surprisingly, the bitterness and astringency, as well as other sensory attributes of NS 5511 (tannin sorghum), were perceived as similar to PAN 8564 (tannin-free sorghum) even though NS 5511 had more than twice the total phenol content of PAN 8564. This suggests not all condensed-tannin containing sorghums have objectionable sensory attributes.

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Section: Resultsmentioning

confidence: 99%

“…This is because phenols are mainly located in the pericarp (bran) of the sorghum caryopsis. 20,22 Aqueous acetone was generally a more efficient extraction solvent of total phenols in sorghum bran than water (bran infusions). Other researchers have also found organic solvents to be better extraction solvents of phenols than water.…”

Section: Resultsmentioning

confidence: 99%

Effects of phenolics in sorghum grain on its bitterness, astringency and other sensory properties

2007

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“…And most of sorghum polyphenols could be extracted either with methanol or aqueous acetone (Youssef et al . ). However, these solvents are toxic and are not acceptable for food industry.…”

Section: Introductionmentioning

confidence: 97%

“…Aqueous acetone and acidified methanol were traditionally used for extraction of phenolic compounds from sorghum shell (Gujer et al 1986;Awika et al 2005b). And most of sorghum polyphenols could be extracted either with methanol or aqueous acetone (Youssef et al 1988). However, these solvents are toxic and are not acceptable for food industry.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Extraction of Phenolics and Antioxidant Capacity from Sorghum (Sorghum bicolor L. Moench) Shell Using Ultrasonic-Assisted Ethanol-Water Binary Solvent

Hou

et al. 2016

Journal of Food Processing and Preservation

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Sorghum shell is a rich source of phenolic compounds. Traditionally used organic solvents for these compounds extraction are toxic and are not acceptable for food industry. This study examined the ultrasonic-assisted ethanol-water binary solvent extraction of phenolic compounds from sorghum shell. The results showed that extraction factors had significant effects on the yields of phenolic compounds. The optimum extraction conditions were solids to 80% ethanol solvent ratio of 1:15 at 50C in a 0.32-W cm 22 ultrasonic intensity bath lasting 10 min in duration and extracted twice. Under these conditions, the yield of total phenolic content (TPC) was 52.23 mg GAE/g with values of 53.22 lmol TE/g for 2,2 0 -azino-bis-(3-ethylbenzothiazoline-6 sulfonic acid) (ABTS) and 77.01 lmol Fe/g for ferric reducing antioxidant power (FRAP). TPC was positively correlated with ABTS and FRAP. The present study would provide theoretical basis for the deep processing and functional food development of sorghum shell comprehensive utilization. PRACTICAL APPLICATIONSAn investigation into the effects of ethanol concentration, ultrasonic power, extraction time, ratio of solvent to raw material, temperature and number of extraction steps on the extraction yields of total phenolic content (TPC), total flavonoid content (TFC) and proanthocyanidins content (PAC) from sorghum shell were performed using a single-factor experiment by ultrasonic assisted extraction (UAE). The UAE optimum process parameters were optimized with regard to the extraction temperature, the amount of solvent and the duration of sonication using orthogonal array design (OAD). Sorghum shell exhibited good antioxidant activity and could be a potentially useful natural source of antioxidants. The present study would provide theoretical basis for the deep processing and functional food development of sorghum shell comprehensive utilization.

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