Search Results (30)

Background: Iron deficiency anemia (IDA) disproportionately affects pregnant women who reside in low-income countries because they predominantly consume staple legumes and tubers such as conventional common beans (CCBs) and white-fleshed sweet potatoes (WFSPs). Such staples are either low in iron or rich in iron absorption inhibitors such as phytates. To fight IDA, a high-iron-biofortified common bean (IBCB) was introduced in Uganda. However, there is limited knowledge about its acceptability among pregnant women. This experimental crossover study determined the sensory acceptability of a low phytate:iron molar ratio dish, WFSP + IBCB (test food), against a high phytate:iron molar ratio dish, WFSP + CCB (control food), among pregnant women in rural Uganda. Their perceptions of consuming the test food during pregnancy were also explored. Methods: A total of 104 pregnant women participated in this study. The sensory attributes (taste, color, aroma, texture, and general acceptability) of the test and control foods were rated using a five-point facial hedonic scale ranging from “dislike very much”, “dislike”, “neutral”, “like”, to “like very much”. An attribute was acceptable if the participant scored either “like” or “like very much”. Focus group discussions (FGDs) were conducted to explore participant perceptions about the factors that may influence them to eat WFSP + IBCB during pregnancy. The chi-square test was used to detect the proportion difference for each sensory attribute within participants between test and control foods, while FGD data were analyzed by thematic analysis. Results: All the sensory attributes were acceptable to the participants and not significantly different between control and test foods (p > 0.05). Participants were willing to consume IBCB if it was affordable, sustainably available, and provided healthy pregnancy outcomes. Conclusions: The sensory attributes of the test food were equally accepted as the control food, suggesting that the consumption of WFSP + IBCB has the potential to replace WFSP + CCB among the study participants. The study participants showed positive perceptions of consuming IBCB if it was accessible, sustainable, affordable, and provided healthy pregnancy outcomes. Full article

Sweet potato (Ipomoea batatas (L.) Lam.; SP) flour enhances food nutrition and bioactivity while functioning as a thickening/gelling agent. This study investigated the impact of two drying methods [hot-air (75 °C/20 h) and freeze-drying (−41–30 °C/70 h)] on the physical–functional properties of flours from three SP varieties: Bonita (white-fleshed), Bellevue (orange-fleshed), and NP1648 (purple-fleshed). Particle size, morphology, water/oil absorption capacities (WAC/OAC), bulk density, swelling power (SwP), water solubility (WS), foaming/emulsifying properties, least gelation concentration (LGC), and gelatinisation temperature (GT) were analysed. Both the drying method and variety significantly influenced these properties. Hot-air-dried flours exhibited bimodal particle distribution, compact microstructure, and aggregated starch granules, yielding higher WAC (≈3.2 g/g) and SwP (≈3.6 g/g). Freeze-dried flours displayed smaller particles, porous microstructure, and fragmented granules, enhancing OAC (≈3.0 g/g) and foaming capacity (≈17.6%). GT was mainly variety-dependent, increasing as Bellevue (74.3 °C) < NP1648 (78.5 °C) < Bonita (82.8 °C), all exceeding commercial potato starch (68.7 °C). NP1648 required lower LGC (10% vs. 16% for others). All flours exhibited high WS (24–39.5%) and emulsifying capacity (≈44%). These results underscore the importance of selecting the appropriate drying method and variety to optimise SP flour functionality for targeted food applications. Freeze-dried flours might suit aerated/oil-retentive products, while hot-air-dried flours could be ideal for moisture-sensitive formulations. Full article

Sweet potato (Ipomoea batatas (L.) Lam.) is a nutrient-dense crop rich in fibre, minerals, and antioxidant compounds, including carotenoids and phenolic compounds, such as anthocyanins. Dehydrating sweet potato (SP) for flour production enhances its value and produces shelf-stable, health-promoting food products. This study investigated the effects of hot-air drying (HAD: 75 °C/20 h) and freeze-drying (FD: −41–30 °C/70 h) on the bioactive composition of flours from three SP varieties: Bonita (white-fleshed), Bellevue (orange-fleshed), and NP1648 (purple-fleshed). Key assessments included the total phenolic content (TPC), the total carotenoid content (TCC), and the total anthocyanin content (TAC) and the antioxidant activity (DPPH and FRAP). The results revealed distinct raw materials’ bioactive profiles: Bellevue was rich in TCC (49.3 mg of β-carotene/100 g db), NP1648 showed elevated TAC (27.3 mg of cyanidin-3-glucoside/100 g db), and Bonita exhibited minimal content of bioactive compounds. Both drying methods yielded significant losses of bioactive compounds, with the TPC decreasing by over 60%, while TAC and TCC losses did not exceed 32%, revealing higher stability. Multivariate analysis indicated that the variety significantly influenced the bioactive profiles more than the drying method. The interaction between carotenoids and anthocyanins and the SP fibrous composition likely contributed to their stability during drying, indicating that FD showed no advantages over HAD. The appealing colours and high antioxidant content of Bellevue and NP1648 flours suggest their potential as ingredients for enhancing foods’ bioactivity and sensory acceptance. Full article

Colored potatoes with red and purple skin or flesh possess significant nutritional value and health benefits due to their rich anthocyanin content. To investigate the genetic mechanisms underlying color formation, the high-anthocyanin-content purple-skinned and purple-fleshed potato line 15-12-16, and the white-skinned and white-fleshed Xiazhai 65 variety were used for ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) analysis, which was conducted to identify and quantify anthocyanins. RNA sequencing was performed to analyze the transcriptome. The results indicated a significant upregulation of genes within the anthocyanidin biosynthesis pathway in the purple potato, while these genes were either downregulated or absent in the white potato. The bHLH, MYB, and WRKY gene families exhibited a greater number of regulatory members, suggesting their pivotal role in color formation. Integrated analysis of the transcriptional and metabolic revealed that 12 differentially expressed genes (DEGs) related to the anthocyanidin biosynthetic had a significant correlation with 18 anthocyanin metabolites. Notably, the key gene St5GT in the anthocyanidin biosynthesis pathway was markedly upregulated in the purple skin and flesh. Furthermore, the overexpression of St5GT (PGSC0003DMG400004573) in tobacco contributed to anthocyanin accumulation. The expression of 10 DEGs was validated through quantitative real-time PCR. In conclusion, these findings provide new insights into anthocyanin biosynthesis and accumulation in purple potatoes, offering valuable candidate genes for the future breeding of colored potatoes. Full article

Individual carotenoids provide significant health benefits to humans, and potatoes are recognized as some of the most stable crops, distinguished by their substantial carotenoid content. To elucidate the accumulation patterns of individual carotenoids in potatoes, we quantified the carotenoid content in yellow- and white-fleshed genotypes across five developmental stages using LC-MS/MS. A total of 22 carotenoids were identified in yellow potatoes, whereas 18 were detected in white potatoes. The yellow-fleshed genotype was characterized by high levels of individual carotenoids and xanthophyll esters, with violaxanthin as the dominant component. The white-fleshed genotype exhibited low concentrations of individual carotenoids and xanthophyll esters, with lutein as the predominant compound. Notably, lutein, violaxanthin, zeaxanthin, antheraxanthin, neoxanthin, violaxanthin myristate, and lutein myristate were consistently detected during the developmental period in both genotypes. Violaxanthin myristate was identified as the dominant xanthophyll ester in both genotypes, showing an increasing trend throughout the tuber development stages. In contrast, xanthophyll esters maintained stable low levels in white-fleshed potatoes while exhibiting increasing types and contents in yellow-fleshed potatoes as the tubers continued to grow. Additionally, violaxanthin exhibited a significant correlation with b*, H°, and C*, suggesting that it may play an important role in forming yellow flesh. Full article

Sweet potatoes are rich in amino acids, organic acids, and lipids, offering exceptional nutritional value. To accurately select varieties with higher nutritional value, we employed liquid chromatography–tandem mass spectrometry (LC-MS/MS) to analyze the metabolic profiles of three types of sweet potatoes (white sweet potato flesh, BS; orange sweet potato flesh, CS; and purple sweet potato flesh, ZS). When comparing CS vs. BS, ZS vs. BS, and ZS vs. CS, we found differences in 527 types of amino acids and their derivatives, 556 kinds of organic acids, and 39 types of lipids. After excluding the derivatives, we found 6 amino acids essential for humans across the three sweet potatoes, with 1 amino acid, 11 organic acids, and 2 lipids being detected for the first time. CS had a higher content of essential amino acids, while ZS had a lower content. Succinic acid served as a characteristic metabolite for ZS, helping to distinguish it from the other two varieties. These findings provide a theoretical basis for assessing the nutritional value of sweet potatoes and setting breeding targets while facilitating the selection of optimal varieties for food processing, medicine, and plant breeding. Full article

Sweet potato (Ipomoea batatas (L.) is regarded among the most crucial crops globally because it is abundant in essential nutrients vital for human health. However, limited comprehensive information is available regarding the nutritional composition of sweet potato, which hinders its optimal utilization. This study investigated the nutritional and chemical composition of sweet potato roots and explored their interrelationships. In total, 86 sweet potato accessions, comprising white, yellow, orange, and purple flesh-colored varieties, were used. A total of 34 components, including nutrients, phytochemicals, and minerals, were identified. Multivariate analysis was performed to assess the relationships among these components. The sweet potato roots were rich in carbohydrates, polyphenols, and minerals. Carbohydrates were primarily composed of total starch (22.6–69.7 g/100 g DW), total soluble sugar (TSS) (10.3–40.0 g/100 g DW), and total dietary fiber (TDF) (7.99–26.0 g/100 g DW). Polyphenols included total caffeoylquinic acids (CQAs) (0.478–14.2 g/kg DW), total anthocyanins (0–2003 mg/kg DW), and β-carotene (0–133 mg/kg DW). The mineral content followed the order: potassium > calcium > phosphorus > sodium > magnesium > iron > manganese > zinc > copper > selenium. White-fleshed sweet potato exhibited high total starch levels (50.4 g/100 g DW) but low TSS levels (21.1 g/100 g DW). Orange-fleshed sweet potato contained high levels of TSS (26.5 g/100 g DW), TDF (17.9 g/100 g DW), and β-carotene (61.4 mg/100 g DW) but low levels of protein (2.99 g/100 g DW) and total starch (43.0 g/100 g DW). Purple-fleshed sweet potato had high levels of phytochemicals, particularly total CQAs (8.17 g/kg DW) and anthocyanins (904 mg/kg DW). Cluster analysis categorized sweet potato accessions into six clusters with unique characteristics. Furthermore, principal component analysis identified accessions with exceptionally high nutritional content. The correlation analysis indicated that starch was negatively correlated with soluble sugar and TDF, whereas CQAs and anthocyanins were highly positively correlated. These findings offer a solid theoretical foundation for sweet potato breeding and utilization. Full article

The continued success of any conventional sweet potato breeding program is limited by knowledge of the inheritance of the traits under study, such as flesh color and tuberous root shape, because of the difficulty of segregating color frequencies by visual separation. The objective of this study was to understand the mode of inheritance of these genetic traits. The cross blocks were established at the Research Institute of Tropical Roots and Tuber Crops (INIVIT-Cuba). Eight parental genotypes of known compatibility were selected, with contrasting phenotypic characteristics to develop segregating populations. To express color objectively, the CIE L*a*b* color space was used (L*: lightness; a* and b*: chromatic coordinates), and four morphometric variables related to the shape and dimensions of the tuberous root were evaluated. From 2419 reciprocal crosses, 2045 botanical seeds and 1764 seedlings were obtained. Incomplete dominance of the white and purple flesh colors over the orange color was observed, as well as transgressive segregation for purple, orange, and white flesh colors and for the shape of the tuberous root. The results allowed us to propose a genetic model of biparental crosses for the improvement of the flesh color of sweet potato (Ipomoea batatas [L.] Lam.), as well as a predictive formula of the progeny to be selected. Full article

Objectives: This study provides an overview of the composition of the raw root flesh of a panel of 22 sweet potato (Ipomoea batatas L.) cultivars, with a focus on bioactive compounds. The large diversity of the proximate and phytochemical compositions observed between cultivars and within and between different flesh colors pointed out the importance of composition analysis and not only color choice for the design of foods with nutritional benefits. Methods: The nutritional composition (starch, protein, total dietary fibers) and bioactive compound composition of 22 cultivars from Reunion Island, maintained in the Vatel Biological Resource Center, were investigated. Results: Orange and purple cultivars stood out from white and yellow cultivars for their higher nutritional composition. Purple sweet potatoes were notable for their high contents of anthocyanins (55.7 to 143.4 mg/g dry weight (DW)) and phenolic compounds, in particular chlorogenic acid and ferulic acid, contributing to antioxidant activities, as well as their fiber content (14.1 ± 2.1% DW). Orange cultivars were rich in β-carotene (47.2 ± 0.7 mg/100 g DW) and to a lesser extent α-carotene (4.8 ± 1.2 mg/100 g DW). In contrast, certain white cultivars demonstrated suboptimal nutritional properties, rendering them less relevant even for applications where the lack of coloration in food is desired. Conclusions: Those characteristics enable the selection of sweet potato varieties to design food products ensuring optimal nutritional benefits and culinary versatility. Full article

Three sweet potato varieties with white-, yellow- and purple-fleshed root tubers were harvested at 100, 120, 140 and 160 days after planting (DAP). Their starch structural, thermal, pasting and digestion properties were measured to reveal the influences of harvesting dates on the physicochemical properties of sweet potato root tuber starch. Though starches from different varieties displayed some differences in physicochemical properties due to their different genetic backgrounds, they were influenced by harvesting date in similar ways. Starches isolated from root tubers at 100 and 160 DAP exhibited lower granule sizes than those at 120 and 140 DAP. The amylose content was higher in root tubers at 100 and 120 DAP than at 140 and 160 DAP. Starches from root tubers at 100 DAP exhibited C_A-type X-ray diffraction patterns, and then the B-type crystallinity gradually increased at later harvesting dates. The different harvesting dates had no significant effects on the short-ranged ordered structure and lamellar thickness of starch, but the lamellar peak intensity decreased significantly at later harvesting dates. Starch had a lower gelatinization temperature and a wider gelatinization temperature range in root tubers at 140 and 160 DAP than at 100 and 120 DAP. The higher peak viscosity and lower pasting temperature were associated with the late harvesting date. The digestion of starch had slight differences among root tubers at different harvesting dates. The harvesting dates of root tubers played more important roles in starch properties than the variety. This study would be helpful for breeders, farmers and sweet potato starch users. Full article

The effects of home cooking methods (e.g., boiling, steaming, oven, and microwave) on the contents phenolic compounds, biogenic amines, and precursor amino acids in colored-fleshed sweet potatoes were investigated in this study. Sixteen genotypes of colored sweet potatoes (cream/white, yellow, orange, and purple pulp) were analyzed using spectrophotometry for their total phenolic compounds, total flavonoids, antioxidant capacity (DPPH and MDA) and pigments. Of these, five genotypes with orange and purple pulps were investigated using HPLC-DAD for their polyphenols, biogenic amines and precursor amino acids. The results revealed that orange-fleshed sweet potatoes contain higher amounts of phenolic compounds, carotenoids, amino acids, and beneficial amines, especially when cooked in a microwave or in an oven, wrapped in aluminum foil. For the purple sweet potatoes, superior quantities of bioactive were found after cooking with steam, microwave, and in the oven with aluminum foil protection. In general, the colored genotypes showed a superior phytochemical profile than the traditionally commercialized ones before and after heat treatments, characterizing them as richer sources of the bioactive compounds of interest for producers, consumers, and industry. Full article

Sweet potatoes (Ipomoea batatas (L.) Lam.) are a widely cultivated member of the Convolvulaceae family. Despite intensive agricultural interest, the metabolic determinants of sweet potato quality remain poorly understood owing to a lack of reliable or systematic sweet potato metabolite analyses. This study aimed to reveal the mechanism of flavonoid biosynthesis using widely targeted metabolomics and qRT-PCR analysis of white (S19) and yellow (BS) sweet potatoes. We found that the PAL, C4H, 4CL, CHS, CHI, IFS, F3H, F3’H, DFR, ANS, and ANR genes were differentially expressed in BS. Upregulation of PAL, C4H, 4CL, and CHS led to the accumulation of large amounts of chalcone, which is highly expressed in yellow flesh, resulting in the yellow color of BS. In S19, the high expression of FLS and the low expression of DFR inhibited pigment accumulation, while the low expression of CHS also inhibited flavonoid synthesis, ultimately leading to the white color. In conclusion, this study identified the main differentially expressed genes and their metabolites in the flavonoid biosynthesis pathway, and preliminarily elucidated the mechanism underlying the different flesh colors in sweet potato, thus providing new insights into the composition and abundance of metabolites in sweet potatoes with different-colored flesh. Full article

The aim of this study was to determine the effect of cultivars on the concentration of antioxidant compounds: total carotenoid content (TC) and vitamin C (VC), and their correlation with the total antioxidant activity (TAA) in 65 potato cultivars (Solanum tuberosum) from 10 countries. The TC content revealed a highly significant effect of the year (Y), cultivar (C) and flesh colour (FC). The TC ranged from 101.5 µg 100 g⁻¹ DM (in cv. Kelly) to 715 µg 100 g⁻¹ DM (in cv. Mayan Gold). The TC values were weakly correlated with years and higher in yellow-fleshed potatoes than in white-fleshed potatoes (319.9 vs. 175.6 µg 100 g⁻¹ DM, respectively). The VC content ranged from 1.0 mg 100 g⁻¹ FM (in cv. Bzura) to 14.8 mg 100 g⁻¹ FM (in cv. Twinner). The content of VC were higher in yellow-fleshed (6.5 mg 100 g⁻¹ FM) than in white-fleshed potatoes (5.8 mg 100 g⁻¹ FM). The highest TAA were observed in cvs. Colleen, Basa, Triplo, Gatsby, Ditta, Twinner, Riviera, Michalina, Damaris, Belmonda, Ambo, Savinja, 12-LHI-6. For these cultivars, the FRAP values were 0.53 µmol TE 100 mg⁻¹ DM and DPPH 0.55 µmol TE 100 mg⁻¹ DM. The lowest TAA were observed in cvs.: Owacja, Mayan Gold, Kokra, Magnolia and Kelly. For them, the FRAP and DPPH values were slightly above 0.2 µmol TE 100 mg⁻¹ DM. It was shown that the concentration of TC in potato tubers has an impact on TAA. Full article

The transcription factor IbbHLH2 has been identified as involved in the biosynthesis of anthocyanins in purple-flesh sweet potatoes. However, little is known about the upstream transcription regulators of the promoter of IbbHLH2 in terms of their involvement in anthocyanin biosynthesis. For this study, the transcription regulators of the promoter of IbbHLH2 were screened via yeast one-hybrid assays in purple-fleshed sweet potato storage roots. Seven proteins, namely IbERF1, IbERF10, IbEBF2, IbPDC, IbPGP19, IbUR5GT, and IbDRM, were screened as upstream binding proteins of the promoter of IbbHLH2. The interactions between the promoter and these upstream binding proteins were verified using dual-luciferase reporter and yeast two-hybrid assays. Furthermore, the gene expression levels of transcription regulators, transcription factors, and structural genes involved in the anthocyanin biosynthesis of different root stages of purple and white-fleshed sweet potatoes were analyzed via real-time PCR. The obtained results indicate that IbERF1 and IbERF10 are key transcription regulators of the promoter of IbbHLH2 and are involved in anthocyanin biosynthesis in purple-fleshed sweet potatoes. Full article

Potatoes are a staple food with high antioxidant properties that can positively affect population health. The beneficial effects of potatoes have been attributed to tuber quality. However, the tuber quality related researches at genetic levels are very few. Sexual hybridization is a powerful strategy for producing new and valuable genotypes with high quality. In this study, 42 breeding potato genotypes in Iran were selected based on appearance characteristics such as shape, size, color, eyes of tubers, and tuber yield and marketability. The tubers were evaluated for their nutritional value and properties, viz. phenolic content, flavonoids, carotenoids, vitamins, sugars, proteins, and antioxidant activity. Potato tubers with white flesh and colored skin had significantly higher levels of ascorbic acid and total sugar. The result showed that higher phenolic, flavonoid, carotenoid, protein concentration, and antioxidant activity were noted in yellow-fleshed. Burren (yellow-fleshed) tubers had more antioxidant capacity in comparison to genotypes and cultivars, which did not differ significantly with genotypes 58, 68, 67 (light yellow), 26, 22, and 12 (white). The highest correlation coefficients in antioxidant compounds were related to total phenol content and FRAP, suggesting that phenolics might be crucial predictors of antioxidant activities. The concentration of antioxidant compounds in the breeding genotypes was higher than in some commercial cultivars, and higher antioxidant compounds content and activity were detected in yellow-fleshed cultivars. Based on current results, understanding the relationship between antioxidant compounds and the antioxidant activity of potatoes could be very helpful in potato breeding projects. Full article