In situ dynamic rheological analysis of raw yam tubers: a potential phenotyping tool for quality evaluation

Most rheological analyses in yam have been done on starch gels, which requires starch extraction from the tubers. In situ rheology bypasses the need of starch extraction and relies on the original cell structure and complex matrix organization under stress or strain. Dynamic rheological properties of tuber from 16 accessions belonging to four yam species (Dioscorea rotundata, D. alata. D. bulbifera and D. dumetorum) were investigated for potential use as a medium throughput phenotyping screening tool that can indicate the quality of yam food products or their industrial potentials.Rheographs of the tubers illustrated differences in the structure of D. bulbifera compared to other yam species. High initial storage modulus (G') of yam parenchyma indicated tubers with strong and rigid structure which do not lose their structural integrity easily on heating. Dioscorea rotundata and D. alata varieties exhibited a lower temperature at which gelatinization took place (Tgel ) equivalent to the irreversible transition during starch gelatinization (75.3 and 79.8 °C) and took shorter time (867 and 958 s, respectively) to reach the G' maximum, compared to other species. The stress relaxation test showed that the higher the dry matter of the tubers, the higher the work to rupture the structure.Rheological characteristics G', loss modulus (G″), swelling capacity and Tgel showed potential as suitable quality indicators for yam products. In situ rheological characterization of yam tubers could be used as an instrumental screening tool to phenotype for quality in yam products. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

Preliminary Studies on the Development and Evaluation of Instant Pounded Yam from Dioscorea alata

Of all the species of Dioscorea , Dioscorea alata possesses higher multiplication ratio and better storability, and requires less capital and labour to produce than the most common specie, Dioscorea rotundata . Exploitation of the industrial potential of D. alata by diversifying its utilisation through the development of novel products will expand its utilisation. This study therefore investigated the potential of developing instant poundo yam flour from D. alata. Instant poundo yam flour was prepared from D. alata by peeling, dicing and immersing yam tubers in sodium metabisulphite solution (800 ppm for 20 min). The tubers were thereafter blanched at 70 \ub0C for either 5 or 10 min, dried in a cabinet dryer at 60 \ub0C for 72 hr, milled and sieved (600 \ub5m) to obtain two experimental samples of poundo yam flours. The proximate composition of the flours was determined using standard methods. Sensory evaluation was conducted to determine the sensory attributes [colour, flavour, taste, textural quality (strecthability, adhesiveness, cohesiveness, smoothness) and general acceptability] of the flours. The two instant poundo yam samples were further compared with a commercial poundo yam in terms of the sensory attributes. There was no significant difference (p 640.05) in the proximate composition of the two experimental instant poundo yam samples but their textural quality differed significantly (p 640.05). Instant poundo yam blanched for 10 min recorded higher sensory scores than the one blanched for 5 min and compared fairly well with the reference sample. An acceptable instant poundo yam has been developed from D. alata

Nutritional properties of ogi powder and sensory perception of ogi porridge made from synthetic provitamin: a maize genotype

Open Access Journal; Published online: 25 Jun 2021Provitamin-A maize (PVA) with increased carotenoid content obtained through conventional breeding techniques has been largely successful in sub-Saharan Africa. This resulted in a need to evaluate their susceptibility, retention, and nutritional content during processing into local foods. This study evaluated the chemical, carotenoid composition, and retention of PVA, the phytic acid content in ogi powder, and the sensory perception of ogi porridge produced traditionally from the three novel PVA maize genotypes (PVA SYN HGAC0 Maize 1; PVA SYN HGBC0 Maize 2; and PVA SYN HGBC1 Maize 3) and one yellow maize variety (control). Chemical composition analyses showed significant differences (p 19 years), 6.2 and 7.7%, respectively. Sensory evaluation showed that the ogi 3 porridge (Maize 3) was the most acceptable, followed by Maize 2. In conclusion, Maize 2 had the highest PVA, true retention of carotenoid, vitamin A contributions, and the second most acceptable ogi porridge with the lowest phytate content

In situ dynamic rheological analysis of raw yam tubers: a potential phenotyping tool for quality evaluation

International audienceBackground: Most rheological analyses in yam have been done on starch gels, which requires starch extraction from the tubers. In situ rheology bypasses the need of starch extraction and relies on the original cell structure and complex matrix organization under stress or strain. Dynamic rheological properties of tuber from 16 accessions belonging to four yam species (Dioscorea rotundata, D. alata. D. bulbifera and D. dumetorum) were investigated for potential use as a medium throughput phenotyping screening tool that can indicate the quality of yam food products or their industrial potentials. Results: Rheographs of the tubers illustrated differences in the structure of D. bulbifera compared to other yam species. High initial storage modulus (G 0) of yam parenchyma indicated tubers with strong and rigid structure which do not lose their structural integrity easily on heating. Dioscorea rotundata and D. alata varieties exhibited a lower temperature at which gelatinization took place (T gel) equivalent to the irreversible transition during starch gelatinization (75.3 and 79.8 °C) and took shorter time (867 and 958 s, respectively) to reach the G 0 maximum, compared to other species. The stress relaxation test showed that the higher the dry matter of the tubers, the higher the work to rupture the structure. Conclusion: Rheological characteristics G 0 , loss modulus (G 00), swelling capacity and T gel showed potential as suitable quality indicators for yam products. In situ rheological characterization of yam tubers could be used as an instrumental screening tool to phenotype for quality in yam products

Effects of NPK and biochar fertilized soil on the proximate composition and mineral evaluation of maize flour

Series of farming practice methods have been employed to increase maize production but there is no adequate information on the effect of these methods on the nutritional and mineral content of organically grown maize. This study investigated the effects of inorganic and biochar fertilized soils on the proximate composition and mineral content of maize. Maize seeds were planted on organically fertilized soil (sawdust and gliricidia biochar), chemically fertilized soil Nitrogen Phosphorus and Potassium (NPK fertilizer), and soil without any amendment as control. The proximate compositions (protein, ash, crude fat, carbohydrate, and moisture) and mineral contents (Na, Mg, K, Ca, Fe, and Zn) of the maize flour samples were determined using standard methods. The results showed that protein content ranged from 4.58% to 7.24% (protein), ash 0.82% to 1.09%, crude fat 3.84% to 4.61%, moisture 9.76% to 10.60%, and carbohydrate 76.85% to 80.31%. There was no significant (p ≤ 0.05) difference among the proximate compositions except for protein and carbohydrate. Maize planted on NPK fertilized soil had the highest crude protein content of 7.24%. Other results obtained included sodium (55.65 mg/100 g), magnesium (35.87 mg/100 g), and iron (6.78 mg/100 g). Maize from soil without amendments was significantly higher than maize from NPK fertilized and biochar fertilized soils. Also, maize from control plot had the highest calcium content value of 48.95 mg/100 g. We concluded that maize planted with NPK fertilizer had higher nutrient than those planted with biochar application. Also, the mineral content of maize planted in control plot was higher than those on the amended soil

A Review of the Use of Near-Infrared Hyperspectral Imaging (NIR-HSI) Techniques for the Non-Destructive Quality Assessment of Root and Tuber Crops

Hyperspectral imaging (HSI) is one of the most often used techniques for rapid quality evaluation for various applications. It is a non-destructive technique that effectively evaluates the quality attributes of root and tuber crops, including yam and cassava, and their food products. Hyperspectral imaging technology, which combines spectroscopy and imaging principles, has an advantage over conventional spectroscopy due to its ability to simultaneously evaluate the physical characteristics and chemical components of various food products and specify their spatial distributions. HSI has demonstrated significant potential for obtaining quick information regarding the chemical composition of the root and tuber, such as starch, protein, dry matter, amylose, and soluble sugars, as well as physical characteristics such as textural properties and water binding capacity. This review highlights the principles of near-infrared hyperspectral imaging (NIR-HSI) techniques combined with relevant image processing tools. It then provides cases of its application in determining crucial biochemical quality traits and textural attributes of roots and tuber crops, focusing on cassava and yam. The need for more information on using NIR-HSI in the quality evaluation of yam and cassava was underscored. It also presents the challenges and prospects of this technology

Nutrient composition, functional and sensory properties of gruel made from local rice

Objective: This study was designed to evaluate the nutrient composition, functional and sensory properties of complementary diets (gruel) developed from local rice.Methods: Local rice grains and paddy rice were fermented and malted respectively, oven dried, milled and sieved into flour. The samples  including the control sample (maize 'ogi') were analyzed for proximate, vitamin, mineral composition, as well as their functional properties using standard methods.Results: The protein value ranged from 5.13-7.90%, while the fat was  between 0.22-0.48%, carbohydrates: 82.63-87.77% and ash between 0.25% -0.92%. The calcium and iron content ranged between  56.8-359.7ppm, and 37.61-69.99ppm respectively. Vitamin composition showed Vitamin A ranged between 160.0-341.79I.U, and Vitamin B 0.69-6.57mg. The 2 functional properties ranged from 0.58-0.95g/ml for bulk density, and swelling index 4.66-18.01%. Fermented maize gruel (control) had the highest values for peak viscosity (2549 cP). Samples were significantly different in organoleptic properties.Conclusion: The fermented rice gruel was more accepted than the malted counterpart although the malted rice sample had higher nutritional content, low bulk density and formed thinner and a less viscous gruel.Key words: Local rice, malting, fermentation, paddy rice, maize 'Ogi'