Sweet Potato Samples Research Articles

Osmotic Treatment of Orange and Pink Sweet Potato-Mass Transfer Rate and Efficiency

Sweet potatoes (Ipomoea batatas) are globally cultivated due to its adaptability, high nutritional value, and short growing season, tolerance to high-temperature soils, low fertility, and minimal pest or disease issues, making it a valuable asset to the food industry. Osmotic treatment, a renowned preservation technique requiring mild temperatures and minimal energy, has gained prominence. Over ten years of research at the Faculty of Technology Novi Sad has pioneered the use of sugar beet molasses as an effective osmotic solution for drying different herbs, fruits, vegetables, and meat. This study specifically focused on osmotically treating samples of pink and orange sweet potatoes in sugar beet molasses (80% w/w) to explore the influence of solution temperatures (20°C, 35°C, and 50°C) and osmotic treatment durations (1h, 3h, and 5h) on mass transfer rate and treatment efficiency. The Principal Component Analysis (PCA) and color correlation analysis were employed to illustrate the connections between different sweet potato samples. Findings indicate that the mass transfer rate peaks at the onset of the process. Particularly with the highest temperature after 1h of osmotic treatment The highest values for RWL and RSG (13.33±0.02, 1.85±0.04 and 11.51±0.02, accordingly) were obtained for both orange ((15.19±0.08 g/(gi.s.w.·s)·105and 4.53±0.06 g/(gi.s.w.·s)·105) and pink sweet potato ((9.91±0.02 g/(gi.s.w.·s)·105 and 3.78±0.04 g/(gi.s.w.·s)·105), respectively. Notably, diffusion is most rapid within the initial three hours, suggesting potential reductions in processing time aligned with these results.

A highly sensitive and selective electrochemical sensor based on polythiourea modified glassy carbon electrode for detecting fenitrothion in vegetables

A sensitive and selective sensor based on a polythiourea-modified glassy carbon electrode (polythiourea/GCE) was fabricated for electrochemical determination of fenitrothion (FT). Cyclic voltammetry and impedance spectroscopy were used to characterize the electrochemical behavior of polythiourea/GCE. The chemical and structural characteristics of the modified electrode were studied with UV-V is and FTIR spectroscopy techniques. The polythiourea (GCE) demonstrated faster electron transfer kinetics, a small charge transfer resistance, and an enhanced electroactive surface area of 0.173 cm2, which was two times greater than that of the bare GCE. The electrochemical behavior of FT at polythiourea/GCE was studied using cyclic voltammetry and square wave voltammetry. The reduction of FT on the surface of the modified electrode followed an adsorption-controlled process, and interestingly, the electrode surface coverage determined from chronocoulometric measurements showed 3.3 times higher accumulation of FT than at the bare GCE. Under optimized experimental parameters, the adsorptive stripping square-wave voltammetric current signal of FT at polythiourea/GCE exhibited an excellent sensitivity of 10.05 μA μM−1, good linearity ranging from 0.05 to 10 µM and 10–50 µM, and low limits of detection and quantification of 2.1 and 7.0 nM, respectively. The selectivity of the sensor was also evaluated in the presence of several common interfering substances, such as nitrophenol, malathion, diazinon, ascorbic acid, K+, Mg2+, and Zn2+ ions, and the percent error was less than ±5 %. The practical application of the suggested electrochemical sensor for FT determination was carried out in tomato, sweet potato, and cabbage samples. The average recoveries of the spiked samples were between 94.3 % and 110 %, indicating that the developed method is accurate for FT determination.

Effect of different pre-treatments on the physical properties, frying kinetics and organoleptic physiognomies of fried sweet potato (Ipomoea batatas) chips

The study explored the effects of different pre-treatments: freezing pre-treatment (FP), osmotic dehydration (OSD) and air-drying pre-treatments (ADP) on the physical and quality properties of fried sweet potato. The physical and quality properties of pre-treated fried sweet potato slices were assessed for percentage weight loss after frying, shrinkage ratio, the kinetics of moisture loss (frying kinetics), organoleptic properties and mathematical modeling of fried sweet potato slices. The results showed that OSD of pre-treated fried sweet potato slices recorded the highest percentage weight loss (46 %) and lowest shrinkage ratio (19 %) after frying compared to the ADP (41.5 %, 36 %) and FP (36.5 %, 46 %) fried sweet potato samples, respectively. OSD pre-treated fried sweet potato preserved the sensory properties of the ADP and FP fried sweet potato compared to the untreated sample. Among the three pre-treatments, OSD was found to enhance the frying kinetics compared to the ADP and FP samples. First order model best fitted well to the experimental results of frying kinetics (R2 > 0.99) compared to Page model.

Osmotic Dehydration Model for Sweet Potato Varieties in Sugar Beet Molasses Using the Peleg Model and Fitting Absorption Data Using the Guggenheim-Anderson-de Boer Model.

This study investigates the applicability of the Peleg model to the osmotic dehydration of various sweet potato variety samples in sugar beet molasses, addressing a notable gap in the existing literature. The osmotic dehydration was performed using an 80% sugar beet molasses solution at temperatures of 20 °C, 35 °C, and 50 °C for periods of 1, 3, and 5 h. The sample-to-solution ratio was 1:5. The objectives encompassed evaluating the Peleg equation's suitability for modeling mass transfer during osmotic dehydration and determining equilibrium water and solid contents at various temperatures. With its modified equation, the Peleg model accurately described water loss and solid gain dynamics during osmotic treatment, as evidenced by a high coefficient of determination value (r2) ranging from 0.990 to 1.000. Analysis of Peleg constants revealed temperature and concentration dependencies, aligning with previous observations. The Guggenheim, Anderson, and de Boer (GAB) model was employed to characterize sorption isotherms, yielding coefficients comparable to prior studies. Effective moisture diffusivity and activation energy calculations further elucidated the drying kinetics, with effective moisture diffusivity values ranging from 1.85 × 10-8 to 4.83 × 10-8 m2/s and activation energy between 7.096 and 16.652 kJ/mol. These findings contribute to understanding the complex kinetics of osmotic dehydration and provide insights into the modeling and optimization of dehydration processes for sweet potato samples, with implications for food processing and preservation methodologies.

Non-destructive detection of trans-caryophyllene in early sweetpotato black spot disease using a QCM gas sensor based on modified CAU-1@ZIF-8 composite

Changes in the content of trans-caryophyllene could identify whether sweetpotatoes are infected with black spot disease. Therefore, in this study, a quartz crystal microbalance (QCM) sensor based on modified CAU-1@ZIF-8 was used for non-destructive detection of sweetpotato black spot. The experimental results showed that the constructed sensor performed best when both modified CAU-1 and ZIF-8 were present. The sensor showed a linear trend (R2 = 0.996, limit of detection (LOD) = 0.55 ppm) in response to trans-caryophyllene in the concentration range of 20–340 ppm with a sensitivity of −0.489 Hz (ppm)−1. The developed gas sensor was successfully used for the detection of trans-caryophyllene in real samples of sweetpotato. The experimental data showed a significant correlation with the results of gas chromatography-mass spectrometry (GC–MS) with a correlation coefficient of 0.970 (p < 0.01). Therefore, it could be used for early warning of black spot disease in sweetpotato.

Forage-cactus based edible coating, packaging, and refrigeration improve the visual and nutraceutical qualities of sweet potatoes

Sweet potatoes have high economic relevance in developing countries. Therefore, the adoption of post-harvest technologies for their conservation for long-distance markets is crucial. In this work, the effect of the combined use of cactus-based edible coating, packaging and refrigeration on the quality of sweet potatoes was evaluated. Four coating and packaging treatments were evaluated: (Control, Coating, Packaging, and Packaging + Coating) and seven storage periods (0, 7, and 14 days at 8 °C, and 17, 20, 23, and 26 days at 23 °C simulate refrigerated transport and shelf conditions respectively). Coating treatments consisted of immersion in 0.04 g L−1 of forage cactus mucilage + 300 mL L−1 glycerol for 1 min. After 14 days of cold storage, sweet potatoes were maintained at 23 °C for up to 26 days. Raw and cooked (microwaved for five minutes) sweet potato samples were evaluated at 0, 7, 14, 17, 20, 23, and 26 days. The refrigerated condition maintained sweet potato quality based on visual analysis for up to 14 days, regardless of the use of the edible coating. However, only packaged sweet potatoes, with or without coating, maintained higher visual scores after transfer to room conditions, exhibiting lower fresh weight loss up to 26 days. Sweet potatoes subjected only to edible coating maintained an acceptable visual appearance until 23 days. Additionally, firmness, visual analysis, DPPH and FRAP antioxidant activity, soluble phenolic and starch contents were more stable in raw and cooked sweet potatoes packaged (with or without coating) for up to 26 days, which is a sufficient time to reach more distant markets.

First Report of Sweet Potato Virus E(SPVE) Infecting Sweet Potato in China.

Sweet potato (Ipomoea batatas [L.] Lam.) is a versatile crop, cultivated in the subtropical and tropical areas, as food, fodder, and industrial raw material crop. In China, sweet potato has been used as a health-care food in recent years, as it contains a wide range of nutrients and xenobiotic phytochemicals. However, viral diseases are major constraint for the sweet potato yield and quality, especially the seed production and quality. Over 30 species of viruses infect sweet potato worldwide (Clark et al. 2012). More recently, a few new viruses infected sweet potato were identified, such as sweet potato virus E (SPVE), which was reported in Korea(Jo et al. 2020). In May 2022, a sweet potato sample (JSXZ1) with virus-like symptom, such as mosaic and vein clearing were collected from sweet potato germplasm Xuzhou resource nursery, Jiangsu Province, China (N34˚16', E117˚18') (Fig. S1A). To investigate the virus disease, the sample JSXZ1 showing the typical symptoms of disease was prepared for Small-RNA (sRNA) deep-sequencing. The sRNA library was constructed using TruSeq™ Small RNA Sample Prep Kits (Illumina, San Diego, USA) and sequenced using the Illumine Hiseq 2500 platform by LC-Bop Technologies (Hangzhou) CO., LTD. The sample was sequenced to obtain 26, 358, 439 raw reads and 22, 969, 139 clean reads after quality control trimming and analysis. The Velvet 1.0.5 software was used to de novo assemble the clean reads (18 to 28 nt) into larger contigs, which were then compared with the nucleotide sequences in the National Center for Biotechnology Information (NCBI) database using the BLASTn algorithm. Viruses found in the sample were sweet potato latent virus (SPLV), sweet potato feathery mottle virus (SPFMV), sweet potato chlorotic stunt virus (SPCSV), sweet potato badnavirus A (SPBV-A) and sweet potato badnavirus B (SPBV-B). Surprisingly, besides the viruses listed above, 28 contigs matched sequences of SPVE isolate GS (MH388502). To verify the result, total RNA was extracted from the sample JSXZ1 and from other leave samples (JSXZ2-JSXZ5) that contained SPFMV, SPVC, SPLV, SPVG respectively stored in lab using FastPure Universal Plant Total RNA Isolation Kit (Vazyme Biotech Co., LTD, Nanjing, China). cDNA was synthesized using random primer (hexadeoxyribonucleotide mixture; pd(N)6). The cDNA serves as template in PCR using a newly designed primer pairs based on SPVE p1 gene (SPVE-F: 5'- TCACCAAAAAGAATGCTACAAC-3'/SPVE-R: 5'-GAAATCCTCCCACTCTCCATA-3'). An expected ~500-bp PCR fragment was obtained in JSXZ1, while none of the fragment was obtained from JSXZ2-JSXZ5 (Fig. S1B). The PCR fragment was cloned into pMD18-T vector (Takara Bio Inc., Beijing, China) and plasmid DNA from transformed Escherichia coli DH5α cell (n=3) were commercially sequenced by Sangon Biotech (Shanghai) Co., Ltd. The sequences of the three fragment clones we obtained were 100% identical when compared. A BLASTN analysis of the sequences revealed that they are specific to SPVE and shared 98.62% nucleotide identity to SPVE GS isolate (MH388502) and one sequence was submitted to GenBank (Accession number OQ948331). To determine the occurrence of SPVE in infected sweet potato plants, a total of 37 leaves samples with viral symptom collected from Shandong Province (n=6) and Jiangsu Province (n=31) were indexed by RT-PCR as described before. Only 9 (24.3%) out of 37 from Shandong (n=1) and Jiangsu (n=8) were positive to SPVE respectively. In addition, five additional viruses (SPFMV, SPVC, SPVG, SPLV, SPCSV) were detected among these 37 samples and always in a mixed infection of two or more viruses. To our knowledge, this is the first report of SPVE infecting sweet potato in China. Sweet potato is an important crop in China and other countries (Zhang et al. 2023). China is the largest sweet potato producer all over the world. In addition, as sweet potato is produced through the vegetative propagation mode, thus, more attention should be paid to detection and monitoring of occurrence of SPVE in China.

Phylogenetic identification of microbes from fermented botanicals used in gluten-free composite flour mixes

Phylogenetic information on microbial communities involved in fermenting botanicals has important implications for the food industry since it can provide a valuable perspective on the diversity, composition, and techno-functional properties and characteristics of the final product. Microbial phylogenetic analysis illustrates the evolutionary history of microbes through visual representational graphs (phylogenetic trees) showing the beginning and advancement of their assemblage.&#x0D; In this study, we used molecular methods to determine the phylogenetic identities of microbes occurring in spontaneously fermented sweet potato, maize, and pigeon pea samples after a 72-hourly evaluation every 12 h. The sequences obtained were edited using the bioinformatics algorithm against similar sequences downloaded from the National Center for Biotechnology Information (NCBI) database using BLASTN and aligned using ClustalX. The neighbor-joining technique was applied to extrapolate the chronicle of the isolates evolution.&#x0D; Molecular identification from the BLASTN results showed the following bacterial isolates: Lysinibacillus macrolides, Klebsiella pneumoniae, Lactococcus lactis, Providencia stuartii, Enterobacter cloacae, Limosilactobacillus fermentum, Lactobacillus fermentum, Staphylococcus edaphicus, and Bacillus flexus, as well as the following fungal isolates: Trichosporon asahii, Mucor irregularis, Cladosporium tenuissimum, and Aspergillus niger. The sequences obtained from the isolates produced an exact match with the NCBI non-redundant nucleotide (nr/nt) database. L. lactis had the highest percentage occurrence for bacteria (38.46%), while T. asahii and A. niger showed the highest occurrence for fungi (37.50%).&#x0D; Identifying and characterizing the microorganisms involved in the fermentation process would allow optimizing fermentation conditions to enhance the quality and nutritional value of the final products.

Advancing sweetpotato quality assessment with hyperspectral imaging and explainable artificial intelligence

The quality evaluation of sweetpotatoes is of utmost importance during postharvest handling as it significantly impacts consumer satisfaction, nutritional value, and market competitiveness. This study presents an innovative approach that integrates explainable artificial intelligence (AI) with hyperspectral imaging to enhance the assessment of three important quality attributes in sweetpotatoes, i.e., dry matter content, soluble solid content, and firmness. Sweetpotato samples of three different varieties, including “Bayou Belle”, “Murasaki”, and “Orleans”, were imaged using a portable visible near-infrared hyperspectral imaging (VNIR-HSI) camera, with a 400–1000 nm spectral range. The extracted spectral data were used to select key wavelengths, develop multivariate regression models, and utilize SHapley Additive exPlanations (SHAP) values to ascertain model effectiveness and interpretability. The regression models (dry matter: R2p = 0.92, RMSEP = 1.50 % and RPD = 5.58; soluble solid content: R2p = 0.66, RMSEP = 0.85obrix, and RPD = 1.72; firmness: R2p = 0.85; RMSEP = 1.66 N and RPD = 2.63) developed with key wavelengths were used to generate prediction maps to visualize the spatial distribution of response attributes, facilitating an improved evaluation of sweetpotato quality. The study demonstrated that the combination of HSI, variable selection, and explainable AI has the potential to enhance the quality assessment of sweetpotatoes, ensuring supplies of higher quality products to consumers.

Determination of Baseline Data on Heavy Metals in Yellow-Flesh Sweet Potato (Ipomoea Batatas) of Trinidad

This study was aimed at determining the level of baseline data on heavy metals in yellow flesh sweet potato (Ipomoea batatas) from six selected agricultural farms in Trinidad and to indicate possible source of contamination risks. Samples of soil and sweet potato tuber, vines and leaves were collected in January 2018.Across all tissue samples of sweet potato, heavy metals were present in the concentration order Zn &gt;Cu&gt;Pb&gt;Ni&gt;Cd. The stem and leaves concentrate more heavy metals than edible tuberous roots. All metal BAF was less than one (BAF&lt;1) and TF&gt; 1 which shows sweet potato effectively translocate these metals from tuber to shoot. Essential micronutrients Zn, Cu and Ni were below WHO ML while the non-essential elements Pb and Cd exceeded the WHO ML limits.

Ecological Risk Assessment and Migration and Accumulation Characteristics of Heavy Metals in Farmland Soil-crop System from Typical Pyrite Mining Area

To evaluate the ecological risk of heavy metals in the soil-crop system in the superimposed high background and human activities from pyrite mining, the heavy metal contents and chemical speciation in soil and crop samples were analyzed, and these data were used to assess the potential ecological risk and factors affecting the migration ability of heavy metals using bioconcentration factors(BCF), potential ecological risk index(RI), risk assessment code(RAC), and correlation analysis. The results indicate that the average Cd, Cu, Pb, and Zn concentrations exceeded the background values of soils in Zhejiang Province and China. Cd had the greatest potential ecological harm, followed by that of Hg. The bioactive components and potential bioactive components of Cd accounted for 46% and 33%, respectively, indicating relatively high bioavailability. Cu and Pb were mainly in potential bioactive components accounting for 60% and 73%, respectively. The As, Cr, Hg, Ni, and Zn were predominantly residual and accounted for >60%, which indicated low biological activity. The RAC levels were in the following order:Cd>Zn>Cu>Pb>Ni>As>Cr>Hg; soil Cd had the highest ecological risk, mainly with high and extremely high levels, whereas other elements had no risk or low risk. Compared with Cd content in soil, only eight rice samples had Cd contents exceeding the safety limit, and sweet potato samples did not exceed the standard. The migration and enrichment capability of rice in order from strong to weak was s follows:Cd>Zn>Cu>Hg>As>Ni>Cr>Pb; the bioactive component of Cd played a significant role in promoting Cd absorption by rice. Soil OM had a bi-directional effect on Cd bioavailability, whereas soil texture had an indirect effect. This comprehensive study shows that the total amount of heavy metals in soil, chemical speciation, biological activities, absorption, and enrichment of heavy metals by crops should be taken into consideration when assessing the ecological risks in the superimposed areas affected by high background and human activities, such as the pyrite mining area.

First report of the root-knot nematode Meloidogyne enterolobii on sweet potato in Georgia, United States.

Five species of root-knot nematodes (RKN), Meloidogyne spp. (M. haplanaria, M. incognita, M. floridensis, M. javanica, and M. arenaria) were detected in 67% of vegetable-growing regions in Georgia, United States (Marquez et al. 2021a, b; Marquez and Hajihassani 2022a, b). In October 2021, two sweet potato (Ipomoea batatas) samples (FF1 and FF2) collected at harvest from a field located in Tattnall County, Reidsville, GA were received for assessment. Symptoms of RKN damage on storage roots included a veiny appearance, surface cracking, and bumpy yellow to brown colored specks (Fig. 1). The population density of RKN second-stage juveniles (J2) was 148 and 180 J2/100 cm3 of soil for FF1 and FF2 samples, respectively. Genomic DNA was isolated by smashing females (n=10) individually in 20 µL of PCR-grade water, followed by freezing at -20°C overnight and thawing at 95°C for 1 min. Each DNA sample was first analyzed with a duplex PCR method using RKN species-specific primer sets for the most common nematode species: Mi2F4/Mi1R1 (M. incognita) and Far/Rar (M. arenaria) and SEC-1F/SEC-1R (M. incognita) and Fjav/Rjav (M. javanica) (Zijlstra et al. 2000; Hajihassani et al. 2022). Since this method failed to identify the RKN species, DNA samples were amplified with Me-F and Me-R primers, specific for diagnosing M. enterolobii (Long et al. 2006). Species-specific PCR produced a 240 bp DNA fragment for FF1 and FF2 samples (Fig. 2), corresponding to M. enterolobii. RKN species identification was confirmed by DNA sequencing using C2F3/1108 and TRNAH/MRH106 primers (Powers et al. 2018; Stanton et al. 1997). Products of C2F3/1108 (GenBank accessions ON320401 and ON320405) were 100% identical with 100% query coverage to a North Carolina M. enterolobii isolate (MN809527), while TRNAH/MHR106 sequences (ON320402 and ON320406) was 99.4-99.8% identical with 89-91% query coverage to a China isolate (MF467278). Measurements [Mean (range)] of body length of M. enterolobii J2 (BL): 454.0 (411.3-485.1) µm; maximum body width (BW): 15.1 (13.8-17.0) µm; stylet length: 14.3 (12.7-15.2) µm; total BL/greatest BW: 30.1 (28.6-31.4) µm; and BL/head end to posterior end of metacorpus: 7.3 (6.5-8.2) µm. Morphological measurements of J2 were comparable to the original description of M. enterolobii Yang and Eisenback. The host suitability of sweet potato varieties [Covington (susceptible to M. enterolobii), Beauregard (susceptible to intermediate), and Regal (resistant)] to the M. enterolobii isolate was assessed (Rutter et al. 2021). Nematode eggs were extracted from skin/bumps of samples FF1 and FF2 by blending (15 sec) and shaking in a 0.5% NaOCl solution (5 min), followed by washing and centrifugation in a standard sucrose solution. Sweet potato slips were transplanted in 10.8-cm-diam. pots filled with sand and steamed field soil (1:1 v/v), and two days after planting, were inoculated with 10,000 eggs of M. enterolobii (six replicates per plant variety). Plants were maintained in a greenhouse at 25-28°C for 85 days in a completely randomized design. Root galling index (scale of 0 to 5) of 4.4, 4.2, and 0.8 (Fig. 3) and reproduction factor (final egg numbers/initial egg number) of 8.2, 7.5, and 0.01 were obtained for Covington, Beauregard, and Regal, respectively confirming that Covington and Beauregard are susceptible to M. enterolobii while Regal is resistant. Meloidogyne enterolobii has not been reported in GA and this is the first report of the nematode on sweet potato in the state. This RKN species is an emerging pest of economic importance in many crops in the Southern United States (Brito et al. 2004; Rutter et al. 2018; Ye et al. 2013). Development of effective short- and long-term control procedures is urgently needed for managing M. enterolobii.

Edukasi Pengolahan Ubi Jalar Ungu dalam Upaya Penurunan Kadar Gula Darah pada Penderita Diabetes Mellitus

Diabetes mellitus is a metabolic disorder in which the pancreas does not produce enough insulin and is characterized by hyperglycemia. Tests to diagnose diabetes include fasting blood sugar (FBS), random blood sugar (RBS) , blood sugar 2 hours after eating (GD2PP) and glycated hemoglobin (HbA1C). Purple sweet potato is a non-pharmacological therapy that has a high fiber content, low glycemic index carbohydrates. Dietary foods containing antioxidants, including anthocyanins, can protect pancreatic β-cells from glucose-induced oxidative stress. Administration of purple sweet potato extract can protect pancreatic β-cells from the harmful effects of free radicals. Study shows that purple sweet potato have different glucose level according to how the sweet potato being processed which is boiled, steamed, grilled and fried purple sweet potato, namely 3.30%, 4.92%, 7.72%, and 7.36%, respectively. So it can be concluded that the lowest glucose content was obtained from the boiled purple sweet potato sample. Anthocyanins that found in purple sweet potatoes (Ipomoea batatas poiret) contain substances that can control blood sugar levels, thus preventing insulin resistance in people with diabetes mellitus. The purpose of this program for the resident of Kavling Senjulung RT 02 RW 09 is to know about non-pharmacological prevention of diabetes and start applying it to control blood sugar for people with diabetes mellitus. The implementation method was carried out by providing education related to purple sweet potato processing and demonstrating how to process it and perform medical examination including blood pressure and random blood sugar (RBS) .

Towards rapidly quantifying and visualizing starch content of sweet potato [Ipomoea batatas (L.) Lam] based on NIR spectral and image data fusion

This study aimed to achieve the rapid quantification and visualization of the starch content in sweet potato via near-infrared (NIR) spectral and image data fusion. The hyperspectral images of the sweet potato samples containing 900–1700 nm spectral information within every pixel were collected. The spectra were preprocessed, analyzed and the 18 informative wavelengths were finally extracted to relate to the measured starch content using the multiple linear regression (MLR) algorithm, producing a good quantitative prediction accuracy with a correlation coefficient of prediction (rP) of 0.970 and a root-mean-square error of prediction (RMSEP) of 0.874 g/100 g by an external validation using a set of dependent samples. The MLR model was further verified in terms of soundness and predictive validity via F-test and t-test, and then transferred to each pixel of the original two dimensional images with the help of a developed algorithm, generating color distribution maps to achieve the vivid visualization of the starch distribution. The study demonstrated that the fusion of the NIR spectral and image data provided a good strategy for the rapidly and nondestructively monitoring the starch content of sweet potato. This technique can be applied to industrial use in the future.

The Effect of Food Processing on the Antioxidant Properties of Ipomoea batatas

It is known that heat treatment can lead to physical and chemical changes that can decrease or alter the properties of food. This work evaluated the influence on the antioxidant activity of boiling, pressure, and microwave cooking processes on three selected sweet potato varieties (purple, orange, and yellow). The samples were analyzed for total phenols and anthocyanin content and antioxidant capacity. The cooking water of the boiling and pressure processing were also analyzed. The results demonstrated that the purple sweet potato had better phenolic compounds, anthocyanins, and antioxidant activity profiles than the other varieties studied. On the other hand, the yellow sweet potato was the variety that showed the lowest antioxidant activity after applying the different culinary processes. Microwave processing, particularly when applied to purple sweet potato samples, seemed to be the most suitable cooking process to extract the bioactive compounds with antioxidant activity. Related to the cooking water, there were discrepancies between the behavior of different sweet potato varieties, since not all the samples followed similar profiles. In conclusion, it is necessary to study sweet potatoes processed through various cooking methods for antioxidant properties and other characteristics, such as texture, flavor, and nutritional value.

Responses of the nutritional value of the orange fleshed ‘Bophelo’ sweet potato (Ipomoea batatas L.) cultivar under various processing techniques

Sweet potato (Ipomoea batatas L.) is a nutrient-dense root crop that is high in antioxidants. However, consumption was observed to decline, mainly as a result of the limited post-harvest processing methods. The boiling method is commonly used, however, leaching of the essential nutrients into the boiling water affects its nutritional value. Therefore, the objective of the study was to investigate the effect of various processing techniques on the nutritional value of the orange fleshed ‘Bophelo’ sweet potato cultivar. A 2 × 3 factorial experiment, arranged in a completely randomized design (CRD), was conducted. Factors A comprised 2 preparations (unpeeled and peeled) methods and factor B comprised three processing (boiling, deep-frying and roasting) methods, which served as treatments, in triplicates. The unprocessed, raw-peeled and unpeeled samples represented the control. Data on vitamin C, beta carotene, total phenolic, starch and protein were determined and recorded. In the peeled form, roasted samples had the highest nutritional accumulation (vitamin C 21.03 mg/100 mL, beta-carotene 64.6 μg/100 g, starch 5.86 g/mL and protein 0.3 mg/L), whereas in the unpeeled form, higher total phenolic (80.7 mg/GAE/g) was retained. The deep-frying method favoured vitamin C (10.00 mg/100 mL) and starch (13.6 g/mL) in the peeled form, but in the unpeeled form, beta-carotene (32.0 μg/100 g), total phenolic (66.2 mg/GAE/g) and protein (1.5 mg/L) were retained. The boiling method retained low levels of vitamin C (3.35 mg/100 mL), beta carotene (54.8 μg/100 g), total phenolic (43.5 mg/GAE/g) and protein (1.3 mg/L) in peeled forms, whereas starch (8.59 g/ml) was retained in the unpeeled samples. In conclusion, the roasting method demonstrated high retention of the tested nutritional value in ‘Bophelo’ sweet potato samples.

Inorganic contaminants (As, Cd, Pb) in peeled and whole potatoes and sweet potatoes

Vegetables are a rich source of macro and micronutrients. Particularly, potatoes and sweet potatoes are widely consumed and are two of the most important food crops in the world. Therefore, contamination of these products due to their content of inorganic contaminants is of great concern. Considering the healthy trend of consuming these tubers and roots with their skins, which are rich in fiber and other nutrients, analysis of the whole product could provide valuable information in relation to their food safety. Therefore, the presence of arsenic (As), cadmium (Cd) and lead (Pb) in peeled and whole potatoes and sweet potatoes was studied. To do so, analytical methods were optimized and validated according to the Association of Official Analytical Collaboration International (AOAC) requirements for food analysis. Although the content of As, Cd and Pb was in most cases more than three times below the maximum allowed levels for these contaminants, the presence of Cd was detected in the samples of whole sweet potato but not in the peeled ones. The same behavior was observed for Pb in most of the sweet potato samples analyzed. This information points to the need to generate information on the whole root and tuber contaminants content, and to have analytical methods available to gather data on the occurrence of these contaminants in the whole vegetable in order to perform their risk assessment according to the consumption habits.

Cost‐effective approaches for acrylamide mitigation in high‐temperature‐processed tuber snacks

Acrylamide is a potential carcinogen produced at higher temperatures while frying, roasting and baking. Starch-rich foods like potatoes are known to produce acrylamide in increasing concentrations than other kinds of foods. This study focuses on mitigation of acrylamide in sweet potato, taro and cassava samples subjected to various heat-treatment processes like oil frying, air frying and baking. Dipping of tuber slices in solutions of garlic, green tea, sodium chloride, yeast, distilled water, whey and blanching prior to frying the tubers were found to be effective pre-treatment methods. However, the effect of the treatments depended on the sample and mode of processing. Yeast was found to produce a significant reduction in the acrylamide production in taro (98.64%) and garlic pretreatment reduced acrylamide in deep fat fried cassava samples up to 95.62%. Similarly, air fried taro samples dipped in distilled water was found to significantly reduce the browning reaction up to 96.51%; primarily due to the fact that distilled water was found to block the reaction between precursors like asparagine and reducing sugars, thereby preventing the formation of acrylamide. Influence of reducing sugar on the formation of acrylamide, when fried at different temperatures was analyzed using Response Surface Methodology (RSM), clearly indicating that the amount of reducing sugars decreased at higher temperatures with increase in acrylamide content. The attempts in the study clearly shows that simple and cost effective pretreatments can be successful applied to produce healthy tuber products with reduced concentration of acrylamide. Practical applications Fried foods are popular among all age groups. However, the acrylamide produced during its processing is a carcinogen of serious concern. Mitigation of this component is an urgent need. The tested simple and cost-effective pre-treatment methods can be applied for acrylamide mitigation in ready-to-eat food processing sector. Moreover these can be practically used by street-food vendors to prepare healthier and safer processed snack foods.

Resequencing of sweetpotato germplasm resources reveals key loci associated with multiple agronomic traits.

Sweetpotato is an important crop that exhibits hexaploidy and high heterozygosity, which limits gene mining for important agronomic traits. Here, 314 sweetpotato germplasm resources were deeply resequenced, and 4 599 509 SNPs and 846 654 InDels were generated, among which 196 124 SNPs were nonsynonymous and 9690 InDels were frameshifted. Based on the Indels, genome-wide marker primers were designed, and 3219 of 40 366 primer pairs were selected to construct the core InDel marker set. The molecular ID of 104 sweetpotato samples verified the availability of these primers. The sweetpotato population structures were then assessed through multiple approaches using SNPs, and diverse approaches demonstrated that population stratification was not obvious for most Chinese germplasm resources. As many as 20 important agronomic traits were evaluated, and a genome-wide association study was conducted on these traits. A total of 19 high-confidence loci were detected in both models. These loci included several candidate genes, such as IbMYB1, IbZEP1, and IbYABBY1, which might be involved in anthocyanin metabolism, carotenoid metabolism, and leaf morphogenesis, respectively. Among them, IbZEP1 and IbYABBY1 were first reported in sweetpotato. The variants in the promoter and the expression levels of IbZEP1 were significantly correlated with flesh color (orange or not orange) in sweetpotato. The expression levels of IbYABBY1 were also correlated with leaf shape. These results will assist in genetic and breeding studies in sweetpotato.

Effect of storage conditions on physico-chemical and sensory acceptability of sweet potato in Gamo Zone, Southern Ethiopia

The effect of different storage conditions (pit, sack, wooden box and clump) on the physico-chemical and sensory acceptability of sweet potatoes was conducted. Sweet potatoes were stored in the four storage conditions and untreated sweet potatoes (control) were used for this study. In four storage conditions, 10 kg of freshly harvested sweet potatoes were stored until the end of four storage months. Per cent of weight loss, sprouting, and spoilage of sweet potatoes data were collected from storage conditions in monthly intervals. All samples were analyzed for physic-chemical properties at Hawassa University, Food Chemistry and Food Microbiology Laboratory, and sensory acceptability was evaluated by using untrained 45 panellists at the end of the storage period. Completely Randomized Design (CRD) was used for storage conditions with three replication. The mean scores of appearance, taste, flavour, smell, and texture of sweet potato in storage conditions at the end of four months and untreated sweet potatoes had not shown significant difference except for overall acceptability of sweet potato. The mean scores of moisture and protein of sweet potato samples had not shown significant (p&lt;0.05) differences in all storage conditions and untreated sweet potatoes. The pit storage scored the highest mean of moisture (71.30), ash (1.53), protein (6.73), fat (4.66) and fiber (1.76) than other storage conditions but less than untreated sweet potato except for fiber content of pit storage. The least mean per cent of weight loss (26.45), sprouting (9.72), and spoilage (2.87) of sweet potato was recorded at pit storage than in other storage conditions at the end of the fourth month. It was concluded that pit is storage preferable to other storage conditions based on weight loss, sprouting, spoilage, better physic-chemical and sensory acceptability, and recommended to farmers for storing sweet potatoes. Further study will be needed on the microbial quality of sweet potatoes in different storage conditions during storage periods.