Composition, Granular Structure, and Pasting Properties of Native Starch Extracted from Plectranthus edulis (Oromo dinich) Tubers

Combined effects of nitrogen and sulfur fertilizers on chemical composition, structure and physicochemical properties of buckwheat starch

Buckwheat starch has attracted worldwide attention in the food industry as a valuable raw material or food additive. Nitrogen (N) and sulfur (S) are two nutrients essential to ensure grain quality. This study investigated the combined application of N fertilizer (0, 45 and 90 kg N ha-1) and S fertilizer (0 and 45 kg SO3 ha-1) on the chemical composition, structure and physicochemical properties of buckwheat starch. The results showed that increasing the fertilizer application decreased amylose content and starch granule size but increased light transmittance, water solubility and swelling power. The stability of the absorption peak positions and the decrease in short-range order degree suggested that fertilization influenced the molecular structure of buckwheat starch. In addition, increases in viscosity and gelatinization enthalpy as well as decreases in gelatinization temperatures and dynamic rheological properties indicated changes in the processing characteristics and product quality of buckwheat-based foods.

Efficacy, kinetics, inactivation mechanism and application of cold plasma in inactivating Alicyclobacillus acidoterrestris spores

As spores of Alicyclobacillus acidoterrestris can survive traditional pasteurization, this organism has been suggested as a target bacterium in the fruit juice industry. This study aimed to investigate the inactivation effect of cold plasma on A. acidoterrestris spores and the mechanism behind the inactivation. The inactivation effect was detected by the plate count method and described by kinetic models. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), the detection of dipicolinic acid (DPA) release and heat resistance detection, the detection and scavenging experiment of reactive species, and cryo-scanning electron microscopy were used to explore the mechanism of cold plasma inactivation of A. acidoterrestris. The results showed that cold plasma can effectively inactivate A. acidoterrestris spores in saline with a 3.0 ± 0.3 and 4.4 ± 0.8 log reduction in CFU/mL, for 9 and 18 min, respectively. The higher the voltage and the longer the treatment time, the stronger the overall inactivation effect. However, a lower gas flow rate may increase the probability of spore contact with reactive species, resulting in better inactivation results. The biphasic model fits the survival curves better than the Weibull model. SEM and TEM revealed that cold plasma treatment can cause varying degrees of damage to the morphology and structure of A. acidoterrestris spores, with at least 50 % sustaining severe morphological and structural damage. The DPA release and heat resistance detection showed that A. acidoterrestris spores did not germinate but died directly during the cold plasma treatment. 1O2 plays the most important role in the inactivation, while O3, H2O2 and NO3- may also be responsible for inactivation. Cold plasma treatment for 1 min reduced A. acidoterrestris spores in apple juice by 0.4 ± 0.0 log, comparable to a 12-min heat treatment at 95 °C. However, as the treatment time increased, the survival curve exhibited a significant tailing phenomenon, which was most likely caused by the various compounds in apple juice that can react with reactive species and exert a physical shielding effect on spores. Higher input power and higher gas flow rate resulted in more complete inactivation of A. acidoterrestris spores in apple juice. What's more, the high inactivation efficiency in saline indicates the cold plasma device provides a promising alternative for controlling A. acidoterrestris spores during apple washing. Overall, our study provides adequate data support and a theoretical basis for using cold plasma to inactivate A. acidoterrestris spores in the food industry.

Impact of variety and drying methods on the physicochemical, functional, and thermal properties of Ethiopian potato (Plectranthus edulis) tuber flour

This study aimed to analyse the physicochemical, structural, functional, and thermal properties of flour from two indigenous Ethiopian Potato (Plectranthus edulis) varieties, Chanqua and Loffo, and to compare with wheat flour (WF). The study also investigated how oven and sun drying methods affected the physicochemical properties of the flours. The results demonstrated a significant distinction (p ≤ 0.05) between the flour samples and WF, attributable to variations in both the varieties and the drying methods except that no significant difference in pH was observed due to the varieties, and the fibre and ash content did not vary significantly with the drying methods. The moisture content (MC) of the flours ranged from 5.72 % in oven-dried Chanqua Ethiopian potato flour (OD-CEPF) to 7.53 % in sun-dried Loffo Ethiopian potato flour (SD-LEPF), both of which were lower compared to WF. The protein content varied from 4.47 % (SD-CEPF) to 5.93 % (OD-LEPF). FTIR tests revealed a significant impact on the structural changes, leading to variations in the location and intensity of infrared absorption peaks, particularly in sensitive regions. Whereas, the XRD patterns showed characteristic B-type diffraction, with a relative crystallinity (RC) of 31.97 % in CEPF and 30.53 % in LEPF having a significant difference (p ≤ 0.05) between them. LEPF had better flow properties than CEPF, with lower Hausner ratio (HR) (1.16 vs. 1.25), Carr's index (CI) (14.51 % vs. 20.26 %), and angle of repose (31.00° vs. 34.67°). It also showed significantly higher (p ≤ 0.05) water absorption capacity (WAC), oil absorption capacity (OAC) and swelling power (SP) properties than CEPF. The study also indicated notable distinctions in the thermal and paring properties of flours. The oven drying method was found to be superior in enhancing the physicochemical properties, with LEPF showing better physicochemical, functional, structural, and thermal properties than CEPF.

Effects of Genotype, Nitrogen, and Sulfur Complex Fertilization on the Nutritional and Technological Characteristics of Buckwheat Flour

The present study investigated the effect of nitrogen fertilization (NF) at the levels of 0, 45, and 90 kg·ha-1 combined with selected sulfur complex fertilization (SCF) levels of 0 and 45 kg·ha-1 on the nutritional and technological characteristics of buckwheat flour from five varieties. The results showed that the genotype was a critical factor affecting the chemical composition and physicochemical properties of buckwheat flour. NF significantly increased protein, total starch, and amylose content as well as mineral composition but decreased particle size, color value, and water hydration properties. However, SCF enhanced the ash content and decreased the protein content but had no significant effect on the pasting temperature. In addition, the combination of NF and SCF significantly reduced granule size, water solubility, viscosity, and rheological properties with increasing fertilization levels. This study can guide the cultivation of buckwheat with the desired physicochemical properties and provide information for buckwheat-based products in the food industry.

Physicochemical Properties of Granular and Gelatinized Lotus Rhizome Starch with Varied Proximate Compositions and Structural Characteristics

As a traditional and popular dietary supplement, lotus rhizome starch (LRS) has health benefits for its many nutritional components and is especially suitable for teenagers and seniors. In this paper, the approximate composition, apparent amylose content (AAC), and structural characteristics of five LRS samples from different regions were investigated, and their correlations with the physicochemical properties of granular and gelatinized LRS were revealed. LRS exhibited rod-shaped and ellipsoidal starch granules, with AAC ranging from 26.6% to 31.7%. LRS-3, from Fuzhou, Jiangxi Province, exhibited a deeper hydrogel color and contained more ash, with 302.6 mg/kg iron, and it could reach the pasting temperature of 62.6 °C. In comparison, LRS-5, from Baoshan, Yunnan Province, exhibited smoother granule surface, less fragmentation, and higher AAC, resulting in better swelling power and freeze-thaw stability. The resistant starch contents of LRS-3 and LRS-5 were the lowest (15.3%) and highest (69.7%), respectively. The enzymatic digestion performance of LRS was positively correlated with ash content and short- and long-term ordered structures but negatively correlated with AAC. Furthermore, the color and network firmness of gelatinized LRS was negatively correlated with its ash content, and the retrograde trend and freeze-thaw stability were more closely correlated with AAC and structural characteristics. These results revealed the physicochemical properties of LRS from different regions and suggested their advantages in appropriate applications as a hydrogel matrix.

Effect of Ecotype and Starch Isolation Methods on the Physicochemical, Functional, and Structural Properties of Ethiopian Potato (Plectranthus edulis) Starch

The Ethiopian potato (Plectranthus edulis) is an annual tuber crop indigenous to Ethiopia. The crop is underutilized and not much studied despite its high yield of starch, which has a good potential to contribute to the effort in meeting the quickly growing demand for starch. In this study, the effects of the ecotype and isolation methods on the physicochemical, functional, structural, and crystalline properties of starches were evaluated. Starches were isolated from two Ethiopian potato ecotypes (Loffo and Chanqua) using distilled water (DW), 0.01% sodium metabisulphite (SMS), and 1M sodium chloride (NaCl) in the isolation media. The results showed that the lowest starch yield was obtained from Chanqua using DW (97.4%), while the maximum was from Loffo using SMS (99.3%). The L* (lightness) and whiteness values of the starches obtained from Loffo were higher than those of Chanqua starches, with NaCl and SMS extractants yielding the highest values. The bulk density, water activity (aw), pH, proximate composition (moisture content, protein, ash, fat, crude fiber, and carbohydrate contents), and techno-functional properties were established. The majority of these parameters varied depending on both the isolation method and the ecotype. The crystallinity pattern of all starches showed B-type diffraction, with differences in diffraction peak intensities between all starches. FTIR tests showed structural changes as a function of the ecotype and isolation procedure used. The Loffo ecotype exhibited considerably better results, and the SMS isolation method was found to be the most effective way to acquire the highest starch quality in most of the characteristics evaluated.

Anchote (Coccinia abyssinica) starch extraction, characterization and bioethanol generation from its pulp/waste

A polysaccharide molecule called starch exists in nature and is cheap, renewable, biodegradable, and readily accessible. The main objective of this project is to extract and characterize anchote (Coccinia abyssinica) starch, as well as to generate bio-ethanol from its pulp/waste. The anchote sample used in this investigation came from Ethiopia's western Oromia region. Anchote (Coccinia abyssinica) starch was extracted, and the pulp from the tuber was peeled and the supernatant isolated for bio-ethanol production. The extracted starch from anchote and bio-ethanol from pulps were characterized by physicochemical, functional properties and FT-IR analysis. The result of physicochemical and functional properties of anchote starch was found to be pH (4.44), WHC (112%), Solubility (5.03%), swelling power (5.781%), Gelatinization temperature (53.33 °C), WAC (2 g/g), bulk density (0.605 g/cm³) and OAC (3 g/g). According to this FTIR research, anchote starch has a chemical structure that is similar to corn, cassava, and potato starch. As the results showing a promising alcoholic content (25% v/v) and the existence of bioethanol being validated by a combustion test, the pulps/wastes recovered from anchote are also good sources of bioethanol. Finally, the FTIR spectroscopic analysis revealed that ethyl alcohol was produced from anchote pulps/waste after acid hydrolysis, fermentation, and distillation.

Correlation analysis on physicochemical and structural properties of sorghum starch

This manuscript analyzed physicochemical and structural properties of 30 different types of sorghum starches based on their apparent amylose content (AAC). Current results confirmed that sorghum starch exhibited irregular spherical or polygonal granule shape with 14.5 μm average particle size. The AAC of sorghum starch ranged from 7.42 to 36.44% corresponding to relative crystallinities of 20.5 to 32.4%. The properties of enthalpy of gelatinization (ΔH), peak viscosity (PV), relative crystallinity (RC), degree of double helix (DD), degree of order (DO), and swelling power (SP) were negatively correlated with AAC, while the cool paste viscosity (CPV) and setback (SB) were positively correlated with AAC. Correlations analyzed was conducted on various physicochemical parameters. Using principal component analysis (PCA) with 20 variables, the difference between 30 different types of sorghum starch was displayed. Results of current study can be used to guide the selection and breeding of sorghum varieties and its application in food and non-food industries.

Effect of Oromo Dinich (Plectranthus edulis) flour supplemented on quality characteristics of teff-maize composite injera

Blending Oromo dinich flours with cereals-based flours significantly enhances the nutritional potential of cereals-based products. Therefore, this study aimed to develop and evaluate the quality of teff-based injera supplemented by underutilized indigenous tuber Oromo dinich (Plectranthus edulis) and maize flours. Fourteen formulations were generated using D-optimal constrained mixture design with a range of maize (5–15%), Plectranthus edulis (5–15%), and teff (70–90%). Statistical evaluation and optimization were done using D-optimal mixture design expert software. The results showed that the supplementation of more Plectranthus edulis flour in the formulations indicated better improvements in terms of protein (10–10.8%), fat (2.4–2.8%), gross energy contents (380.7–391.9 kcal/100g), total phenolic content (8.6–15.8 mg GAE/g) and total antioxidant capacity (66.20–82.7%) at the concentration of 3.32 mg/mL. The sensory acceptability of the injera was significantly (p < 0.05) liked in terms of aroma with increasing the ratio of Plectranthus edulis and maize flours. The optimum value of the blending ratio was 77.6% teff, 13.1% maize, and 9.3% Plectranthus edulis flours with desirable nutritional composition of injera, which varied for protein (10.7–10.8%), fat (2.62–2.8%) and energy (388.3–391.9 kcal/100g) and overall acceptance (5.5–6.3) with the desirability of 0.66. The optimization results indicated that supplementing Plectranthus edulis flour up to 10% with teff-maize composite flours were acceptable in terms of nutritional composition and sensory quality. Thus, supplementing underutilized indigenous Plectranthus edulis tuber flour with teff-maize flours significantly enhanced the nutritional potential of injera products.

Relationships between X-ray Diffraction Peaks, Molecular Components, and Heat Properties of C-Type Starches from Different Sweet Potato Varieties

C-type starches with different proportions of A- and B-type crystallinities have different intensities and crystallinities of X-ray diffraction peaks. In this study, the intensities and crystallinities of X-ray diffraction peaks, molecular components and heat properties of C-type starches were investigated in seven sweet potato varieties, and their relationships were analyzed. The intensity and crystallinity of a diffraction peak at 5.6° were significantly positively correlated to the DP6-12 branch-chains of amylopectin and significantly negatively correlated to the true amylose content (TAC) determined by concanavalin A precipitation, gelatinization temperature, gelatinization enthalpy, water solubility at 95 °C, and pasting temperature. The intensity of diffraction peaks at 15° and 23° were significantly positively correlated to the gelatinization temperature and pasting temperature and significantly negatively correlated to the pasting peak viscosity. The significantly positive relationships were detected between the crystallinity of a diffraction peak at 15° and the DP13-24 branch-chains of amylopectin, gelatinization conclusion temperature and water solubility, between the crystallinity of diffraction peak at 17–18° and the TAC, gelatinization onset temperature, water solubility and pasting temperature, between the crystallinity of a diffraction peak at 23° and the gelatinization conclusion temperature and pasting peak time, and between the total crystallinity and the TAC, gelatinization conclusion temperature, water solubility and pasting temperature. The score plot of principle component analysis showed that the molecular components and heat property parameters could differentiate the C-type starches and agreed with their characteristics of X-ray diffraction peaks. This study provides some references for the utilizations of C-type starches.

Physicochemical Characterization of Thirteen Quinoa (Chenopodium quinoa Willd.) Varieties Grown in North-West Europe-Part II

Quinoa cultivation has gained increasing interest in Europe but more research on the characteristics of European varieties is required to help determine their end use applications. A comparative study was performed on 13 quinoa varieties cultivated under North-West European field conditions during three consecutive growing seasons (2017-2019). The seeds were milled to wholemeal flour (WMF) to evaluate the physicochemical properties. The WMFs of 2019 were characterized by the highest water absorption capacity (1.46-2.06 g/g), while the water absorption index (WAI) between 55 °C (2.04-3.80 g/g) and 85 °C (4.04-7.82 g/g) increased over the years. The WMFs of 2018 had the highest WAI at 95 °C (6.48-9.48 g/g). The pasting profiles were characterized by a high viscosity peak (1696-2560 mPa.s) and strong breakdown (-78-643 mPa.s) in 2017. The peak viscosity decreased in 2018 and 2019 (823-2492 mPa.s), while breakdown (-364-555 mPa.s) and setback (19-1037 mPa.s) increased. Jessie, Summer Red, Rouge Marie, Vikinga, and Zwarte WMFs were characterized by low WAIs and high shear resistance. Bastille WMF developed high viscosities and, along with Faro WMF, showed a high breakdown. The wide variation in physicochemical properties suggests that the potential food applications of WMFs depend on the variety and growing conditions.

Comparison of the Chemical and Technological Characteristics of Wholemeal Flours Obtained from Amaranth (Amaranthus sp.), Quinoa (Chenopodium quinoa) and Buckwheat (Fagopyrum sp.) Seeds

A sound fundamental knowledge of the seed and flour characteristics of pseudocereals is crucial to be able to promote their industrial use. As a first step towards a more efficient and successful application, this study focuses on the seed characteristics, chemical composition and technological properties of commercially available pseudocereals (amaranth, quinoa, buckwheat). The levels of starch, fat, dietary fiber and minerals were comparable for amaranth and quinoa seeds but the protein content is higher in amaranth. Due to the high amount of starch, buckwheat seeds are characterised by the lowest amounts of fat, dietary fibre and minerals. Its protein content ranged between that of amaranth and quinoa. Buckwheat seeds were larger but easily reduced in size. The lipid fraction of the pseudocereals mostly contained unsaturated fatty acids, with the highest prevalence of linoleic and oleic acid. Palmitic acid is the most abundant unsaturated fatty acid. Moreover, high levels of P, K and Mg were found in these pseudocereals. The highest phenolic content was found in buckwheat. Amaranth WMF (wholemeal flour) had a high swelling power but low shear stability. The pasting profile strongly varied among the different quinoa WMFs. Buckwheat WMFs showed high shear stability and rate of retrogradation.

The effect of peeling and cooking processes on nutrient composition of Oromo dinich (Plectranthus edulis) tuber

The effects of peeling and cooking processes (boiling, steaming and baking) on the proximate, amino acids, mono, and disaccharides content of Oromo dinich (Plectranthus edulis) tubers from selected landraces were investigated. The effect of peeling on the crude protein, reducing sugars and sucrose content of the tuber was not consistent across the landraces. Crude protein reduced in landraces DHSer, IWsh, DGArr, and DGArw but increased in landrace CWsh. Reducing sugars (fructose, glucose, and maltose) increase in landraces LWsh, CWsh, DGArr, and DOJiw but reduced in landrace DOSu. Sucrose reduced in landraces IWsh and LWsh but increased in landrace CWsh on dry matter basis. Peeling significantly reduced the dry matter, ash and crude fiber content of the tubers. Dry matter reduced in landraces CWsh, DGArr, and DGArw; ash reduced in landraces DHSer and DGArw; crude-fiber reduced in landraces DOSu, DOSer, LWsh, CWsh, DGArr, and DGArw. On contrary, peeling significantly increased the crude fat, sum of total amino acids content and energy density of the tubers. Crude fat increased in landrace DOSu, IWsh, CWsh, DGArr, and DOJiw. Sum of total amino acids increased in landraces DOSu, DOJiw, and DGArw. Energy density (KJ/100 g dm) increased in landraces DOSu, DHSer, IWsh, and DOJiw. Boiling and steaming significantly increased the ash content of the tubers in landrace LWsh. Steaming and baking significantly increased crude fiber in landraces IWch and CWsh, and carbohydrate content of the tubers in landrace LWsh. Boiling, steaming and baking significantly reduced the crude fiber and the energy density of the tubers in landrace LWsh. Baking significantly reduced the moisture content of the tubers in landraces IWch, LWsh and CWsh. Boiling significantly reduced reducing sugars and crude fat content of the tubers in landraces IWch, LWsh and CWsh. The reduction in reducing sugar and crude fat content most likely is due to leaching and the presence of essential oils respectively. Thus to get the best possible nutritional benefits from P.edulis tubers, cooking with their skin under optimized operation recommended.