scholarly journals Effects of Different Isolation Media on Structural and Functional Properties of Starches from Root Tubers of Purple, Yellow and White Sweet Potatoes

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2135 ◽  
Author(s):  
Ahui Xu ◽  
Ke Guo ◽  
Tianxiang Liu ◽  
Xiaofeng Bian ◽  
Long Zhang ◽  
...  

Different-colored sweet potatoes have different contents of pigments and phenolic compounds in their root tubers, which influence the isolation of starch. It is important to justify the identification of the most suitable isolation medium of starch from different colored root tubers. In this study, starches were isolated from root tubers of purple, yellow and white sweet potatoes using four different extraction media, including H2O, 0.5% Na2S2O5, 0.2% NaOH, and both 0.5% Na2S2O5 and 0.2% NaOH. Their structural and functional properties were investigated and compared among different extraction media. The results showed that the granule size, apparent amylose content, lamellar peak intensity, thermal properties, and pasting properties were different among different-colored sweet potatoes due to their different genotype backgrounds. The four extraction media had no significant effects on starch structural properties, including apparent amylose content, crystalline structure, ordered degree, and lamellar peak intensity, except that the NaOH and Na2S2O5 treatment were able to increase the whiteness of purple and yellow sweet potato starches. The different extraction media had some effects on starch functional properties, including thermal properties, swelling power, water solubility, and pasting properties. The above results indicated that the H2O was the most suitable extraction medium to simply and fast isolate starch from root tubers of different-colored sweet potatoes.

Author(s):  
X.Y. Chen ◽  
X.W. Ma ◽  
J.Y. Wen ◽  
X.C. Liu ◽  
X.R. Yu ◽  
...  

Background: Legume is well known for its high nutrition and health care values. Considering that starch is the main carbohydrate in legume, its properties directly affect the development and utilization of legume resources. Methods: Starches were extracted from the seeds and root tubers of five legumes. The morphological, structural and functional properties of the starches were investigated and compared using scanning electron microscopy, X-ray diffraction and attenuated total reflectance-Fourier transform infrared spectroscopy.Result: The granules of kudzu, broad bean and pigeon pea starches were kidney-shaped with a large size, while groundnut and white pea starches were small granules with a mixture of irregularly polyhedral and spherical shape. The five legume starches had different apparent amylose contents and exhibited remarkably different crystalline properties. Among the samples, the relative crystallinity of kudzu starch was the highest, while pigeon pea starch had the highest short-range ordered degree. The swelling power and water solubility of the five legume starches were also varied. Furthermore, white pea starch is more susceptible to acid and enzymatic hydrolysis than the four other starches. The results are important for the processing and utilization of legume starches and can provide reference for the development of legume-based functional food.


2018 ◽  
Vol 61 (3) ◽  
pp. 1165-1174 ◽  
Author(s):  
Manjot Singh ◽  
Akinbode Adedeji ◽  
Dipak Santra

Abstract. Evaluation of the postharvest properties of nine proso millet cultivars was carried out to determine their physical and engineering properties, which are very useful for designing appropriate systems for process operations such as sorting, drying, heating, cooling, and milling. Nine cultivars of proso millet comprising waxy and non-waxy types, namely Cope, Earlybird, Huntsman, Minco, Plateau, Sunrise, Rise, Dawn, and Panhandle, were obtained from the Panhandle Research and Extension Center, University of Nebraska, Scottsbluff. Results showed significant (p < 0.05) differences in their physical properties, such as sphericity, volume, bulk density, porosity, and angle of repose, which ranged from 0.86 to 0.91, from 3.94 to 5.14 mm3, from 765.49 to 809.67 kg m-3, from 42.49% to 44.20%, and from 22.98° to 25.74°, respectively. The cultivars were also evaluated for their pasting and gelatinization properties, and high correlation was found between amylose content and onset temperature (r = -0.94), peak gelatinization temperature (r = -0.92), peak viscosity (r = 0.84), final viscosity (r = 0.91), and setback viscosity (r = 0.90). The understanding of these basic physical and functional properties of proso millet cultivars will form the foundation for processing them into value-added products. Keywords: Chemical properties, Pasting properties, Proso millet.


2017 ◽  
Author(s):  
◽  
Bruce Mawoyo

Amadumbe commonly, known as taro is a traditionally underutilised tuber crop in Southern Africa. Nutritionally, amadumbe corms contain appreciable levels of carbohydrate mainly in the form of starch which is resistant to digestion. It also contains mucilage, a soluble fibre, which is good for the human digestive health. Thus, amadumbe starch and mucilage can be used as functional ingredients in food formulations. The aim of this research was to investigate the effects of genotypes and growth location on the physicochemical properties of amadumbe flour and starch. Eighteen (18) amadumbe genotypes grown in Roodeplaat, Gauteng and Umbumbulu, Kwazulu-Natal, South Africa, were studied. Roodeplaat received a lower annual average rainfall (514 mm) and high environmental temperature (24oC) compared to Umbumbulu (828 mm, 19oC) during the cropping season. Specifically, the influence of growth location and genotypes on the chemical composition (proximate composition and mineral contents) as well as the functional properties of amadumbe flours were investigated. Furthermore, starch was extracted and its physicochemical and functional properties were also studied. The carbohydrate contents (73-81%) of amadumbe flours were substantially high and varied with growth location. Mucilage contents (6-9%) were very low across genotypes in both locations. Water absorption and oil absorption capacities positively correlated to carbohydrates and mucilage in the flour irrespective of growth locations. Swelling power and solubility index was influenced by the amylose content of the flour. Genotype and growth location significantly affected the pasting properties of amadumbe flour. The pasting temperature was very high (approx. 90oC) across genotypes in both locations, while peak viscosity differed significantly (54-242 RVU) for genotypes grown in different environments. The amylose contents (0-14.4%) of amadumbe starches were low and varied significantly with growth location and among genotypes. Three genotypes, G2, G20, and G21 grown in Roodeplaat lacked amylose. Amadumbe starches showed reflective peaks at 2θ=15o and doublet at 17o, 18o and 24o typical of A-type starches. Amadumbe genotypes had small sized (1-5 µm) and polygonal starch granules. Functional properties including water absorption, swelling power, gelatinisation temperature and peak viscosity significantly positively correlated with amylose content. These findings further suggest that water availability could have a major effect on starch synthesis as the two locations received a different amount of rainfall during the growing season. Findings from this study are important for future improvement programmes and selection of appropriate genotypes for industrial production or food application of amadumbe flour and starch.


Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2132 ◽  
Author(s):  
Juan Wang ◽  
Ke Guo ◽  
Xiaoxu Fan ◽  
Gongneng Feng ◽  
Cunxu Wei

The dry root tuber of Apios fortunei contained about 75% starch, indicating that it is an important starch resource. Starch displayed spherical, polygonal, and ellipsoidal granules with central hila. Granule sizes ranged from 3 to 30 μm with a 9.6 μm volume-weighted mean diameter. The starch had 35% apparent amylose content and exhibited CA-type crystalline structure with 25.9% relative crystallinity. The short-range ordered degree in the granule external region was approximately 0.65, and the lamellar thickness was approximately 9.6 nm. The swelling power and water solubility began to increase from 70 °C and reached 28.7 g/g and 10.8% at 95 °C. Starch had typical bimodal thermal curve in water with gelatinization temperatures from 61.8 to 83.9 °C. The 7% (w/w) starch-water slurry had peak, hot, breakdown, final, and setback viscosities of 1689, 1420, 269, 2103, and 683 mPa s, respectively. Rapidly digestible starch, slowly digestible starch, and resistant starch were 6.04%, 10.96%, and 83.00% in native starch; 83.16%, 15.23%, and 1.61% in gelatinized starch; and 78.13%, 17.88%, and 3.99% in retrograded starch, respectively. The above physicochemical properties of A. fortunei starch were compared with those of maize A-type starch, potato B-type starch, and pea C-type starch. The hierarchical cluster analysis based on starch structural and functional property parameters showed that A. fortunei and pea starches had similar physicochemical properties and were more related to maize starch than potato starch.


2021 ◽  
pp. 108201322110692
Author(s):  
Abdolkhalegh Golkar ◽  
Jafar Mohammadzadeh Milani ◽  
Ali Motamedzadeghan ◽  
Reza Esmaeilzadeh Kenari

Thermal-ultrasound treatment is a green technology that can significantly alter the structural and functional properties of starches. This research extend the effect of at different temperatures (25 °C, 45 °C, and 65 °C) and times (30 and 60 min) on the physicochemical, structural, and rheological properties of corn starch was studied. Amylose content, solubility, swelling power, and the least gelling content increased with increasing temperature and time. Starch treated at 45 °C for 30 min had the lowest syneresis among all treatments. Thermal-ultrasound treatment at 25 °C and 65 °C for 60 min caused increasing paste clarity. Microscopic observations demonstrated that the starch granules were agglomerated at 65 °C. Although the crystallinity of samples decreased from 35.42% to 8.94%, the storage modulus was more than the loss modulus during the frequency sweep test. Pasting properties showed that pasting temperatures shifted to higher values after treatment. Nonetheless, the maximum viscosity decreased, and the final viscosity of the treated samples demonstrated that short-term retrogradation could deteriorate. Results showed that thermal-ultrasound is a viable technique for starch modification compared to conventional thermal and ultrasound treatments.


Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2312 ◽  
Author(s):  
Zheng Li ◽  
Ke Guo ◽  
Lingshang Lin ◽  
Wei He ◽  
Long Zhang ◽  
...  

Green banana fruit is an important starch resource that consists of flesh and peel. The physicochemical properties of flesh starch have been widely studied; however, those of peel starch have hardly been studied, leading to the waste of peel. In this study, the physicochemical properties of the starches from the flesh and peel of green banana fruit were investigated and compared. The dry flesh and peel had 69.5% and 22.6% starch content, respectively. The starch had oval and irregular granules with eccentric hila. Their starches had similar bimodal size distribution; the volume-weighted mean diameter was approximate 17 μm, and the peel starch had a slightly smaller granule size than the flesh starch. The maximum absorption wavelength was higher in peel starch than in flesh starch. The apparent amylose content of flesh and peel starch was 21.3% and 25.7%, respectively. The flesh and peel starches both exhibited B-type crystalline structures and had similar relative crystallinity, short-range ordered degrees, and lamellar structures. The swelling power was similar between flesh and peel starches, but the water solubility was higher in peel starch than in flesh starch at 95 °C. The peel starch had a higher gelatinization temperature than flesh starch, but their gelatinization temperature range and enthalpy were similar. Both flesh and peel starches showed a diphasic hydrolysis dynamic, but peel starch had higher resistance to porcine pancreatic α-amylase hydrolysis than flesh starch. The contents of rapidly digestible starch, slowly digestible starch, and the resistant starch of flesh and peel were 1.7%, 4.3%, 94.1% and 1.4%, 3.4%, 95.2%, respectively, for native starch, and 73.0%, 5.1%, 21.9%, and 72.3%, 4.5%, 23.2%, respectively, for gelatinized starch.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Farahin N. N. Syed ◽  
Muta H. Zakaria ◽  
Japar S. Bujang ◽  
Annie Christianus

Several aquatic macrophytes such as Colocasia esculenta, Eleocharis dulcis, Nelumbo nucifera, Sagittaria sagittifolia, Trapa bispinosa, and Typha angustifolia possessed carbohydrate mainly in their storage and reproductive parts. Starch morphology, total starch, and amylose content of these six freshwater plant species were determined. Their functional properties, i.e., starch crystallinity, thermal properties, and rheological behaviour were assessed. Large starch granules were in N. nucifera rhizome (>15 μm), medium-sized was N. nucifera seed (8-18 μm), while the rest of the starches were small starch granules (<8 μm). Shapes of the starch granules varied from oval and irregular with centric hilum to elongated granules with the eccentric hilum. Eleocharis dulcis corm starch had significantly higher total starch content (90.87%), followed by corms of C. esculenta (82.35%) and S. sagittifolia (71.71%). Nelumbo nucifera seed starch had significantly higher amylose content (71.45%), followed by T. angustifolia pollen (36.47%). In comparison, the waxy starch was in N. nucifera rhizome (7.63%), T. bispinosa seed (8.83%), C. esculenta corm (10.61%), and T. angustifolia rhizome (13.51%). Higher resistant starch was observed mostly in rhizomes of N. nucifera (39.34%)>T. angustifolia (37.19%) and corm parts of E. dulcis (37.41%)>S. sagittifolia (35.09%) compared to seed and pollen starches. The XRD profiles of macrophytes starches displayed in all the corms and N. nucifera seed had A-type crystallinity. The T. bispinosa seed had CA-type, whereas the rest of the starches exhibited CB-type crystallinity. Waxy starches of C. esculenta corm had higher relative crystallinity (36.91%) and viscosity (46.2 mPa s) than regular starches. Based on thermal properties, high-amylose of N. nucifera seed and T. angustifolia pollen resulted in higher gelatinization enthalpy (19.93 and 18.66 J g-1, respectively). Starch properties showed equally good potential as commercial starches in starch-based food production based on their starch properties and functionality.


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