Exploration of Raw Pigmented-Fleshed Sweet Potatoes Volatile Organic Compounds and the Precursors.

Sweet potato provides rich nutrients and bioactive substances for the human diet. In this study, the volatile organic compounds of five pigmented-fleshed sweet potato cultivars were determined, the characteristic aroma compounds were screened, and a correlation analysis was carried out with the aroma precursors. In total, 66 volatile organic compounds were identified. Terpenoids and aldehydes were the main volatile compounds, accounting for 59% and 17%, respectively. Fifteen compounds, including seven aldehydes, six terpenes, one furan, and phenol, were identified as key aromatic compounds for sweet potato using relative odor activity values (ROAVs) and contributed to flower, sweet, and fat flavors. The OR sample exhibited a significant presence of trans-ß-Ionone, while the Y sample showed high levels of benzaldehyde. Starch, soluble sugars, 20 amino acids, and 25 fatty acids were detected as volatile compounds precursors. Among them, total starch (57.2%), phenylalanine (126.82 ± 0.02 g/g), and fatty acids (6.45 µg/mg) were all most abundant in Y, and LY contained the most soluble sugar (14.65%). The results of the correlation analysis revealed the significant correlations were identified between seven carotenoids and trans-ß-Ionone, soluble sugar and nerol, two fatty acids and hexanal, phenylalanine and 10 fatty acids with benzaldehyde, respectively. In general, terpenoids and aldehydes were identified as the main key aromatic compounds in sweet potatoes, and carotenoids had more influence on the aroma of OR than other cultivars. Soluble sugars, amino acids, and fatty acids probably serve as important precursors for some key aroma compounds in sweet potatoes. These findings provide valuable insights for the formation of sweet potato aroma.

Effects of microwave radiation on the physicochemical properties, structure, and digestibility of the synthesized different crystal forms of malic acid starch ester.

The effects of microwave combined with L-malic acid treatment on the degree of substitution (DS), structure, physicochemical properties, and digestibility of sweet potato starch (A-type), potato starch (B-type), and pea starch (C-type) were evaluated. The order of DS obtained was: DSM-POS > DSM-SPS > DSM-PES. Fourier transform-infrared spectroscopy (FT-IR) showed that the obtained modified starch produced a new absorption band at 1735 cm-1. Scanning electron microscopy (SEM) and polarized light microscopy indicated that different types of native starches exhibited different granular morphologies and appeared to have different degrees of damage, but still had polarized crosses after modification. Sweet potato starch had the smallest particle size, while potato starch had the largest. X-ray diffractometry (XRD) showed that the modified starches still retained the same crystal structure as the native starches, but the relative crystallinity decreased. The apparent viscosity and swelling power of modified starches dropped, but their water/oil holding capacity, amylose content, and resistant starch content all increased. The results demonstrate that the degree of influence on the structure, physicochemical properties, and digestibility of different starches varies under the same modification conditions.

Hydrophobic Components in Light-Yellow Pulp Sweet Potato (Ipomoea batatas (L.) Lam.) Tubers Suppress LPS-Induced Inflammatory Responses in RAW264.7 Cells via Activation of the Nrf2 Pathway.

Sweet potato is a crop that is widely consumed all over the world and is thought to contribute to health maintenance due to its abundant nutrients and phytochemicals. Previous studies on the functionality of sweet potatoes have focused on varieties that have colored pulp, such as purple and orange, which contain high levels of specific phytochemicals. Therefore, in the present study, we evaluated the anti-inflammatory effects of light-yellow-fleshed sweet potatoes, which have received little attention. After freeze-drying sweet potatoes harvested in 2020, extracts were prepared from the leaves, stems, roots, and tubers in 100% ethanol. Mouse macrophage-like cell line RAW264.7 cells were cultured with 10 µg/mL of the extracts and induced lipopolysaccharide (LPS)-stimulated inflammation. Of the extracts, the tuber extracts showed the highest suppression of LPS-induced interleukin-6 (IL-6) gene expression and production in RAW264.7, which was attributed to the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) oxidative stress response pathway. In addition, preparative high-performance liquid chromatography (HPLC) experiments suggested that hydrophobic components specific to the tuber were the main body of activity. In previous studies, it has been shown that the tubers and leaves of sweet potatoes with colored pulp exhibit anti-inflammatory effects due to their rich phytochemicals, and our results show that the tubers with light-yellow pulp also exhibit the effects. Furthermore, we were able to show a part of the mechanism, which may contribute to the fundamental understanding of the treatment and prevention of inflammation by food-derived components.

Sweet potato flour (Ipomoea batatas) as natural antioxidant on carcass yield and meat physicochemical characteristics of Creole chickens of Mexico and Cobb 500.

Antioxidants are considered functional additives against oxidative stress since they avoid nutritional decline in the meat. The main objective of the present study is to evaluate the effect of sweet potato flour (SPF) as a natural antioxidant on carcass yield and physicochemical characteristics of Creole chickens of Mexico (CChM) and Cobb 500 broilers. In total, 210 chickens (105 CChM and 105 Cobb 500 chickens) were randomly assigned to three treatments: 0, 500, and 1000 mg of SPF kg-1 of feed. The Cobb 500 chickens showed higher carcass yield (hot and cold), breast, and breast fillet, whereas the CChM had higher thigh yield (P ≤ 0.05). The yield on the previously mentioned variables was not affected by the inclusion levels of SPF. The initial pH differed because of the effect of the chicken's genotype and the addition of SPF, which was higher on Cobb 500 chicken and on those that were not supplemented with SPF. The birds' skin that consumed SPF presented higher yellowness after 24 h (P ≤ 0.05). CChM manifested a higher dry matter and protein content and a lower content of ash and fat (P ≤ 0.05). In conclusion, Cobb 500 chickens present a higher carcass yield and its components, in addition to a less acid pH; however, CChM offer a higher nutritional contribution, whereas the 500 and 1000 mg addition of SPF increases the skin yellowness, which makes it an alterorganic as a pigment on broiler chicken production.

Development of thermoultrasound assisted blanching to improve enzyme inactivation efficiency, drying characteristics, energy consumption, and physiochemical properties of sweet potatoes.

Thermoultrasound (USB) as a promising alternative to traditional hot water (HWB) blanching was employed to blanch sweet potatoes and its influence on enzyme activity, drying behavior, energy consumption and physiochemical properties of sweet potatoes were investigated. Results showed that successive increases in blanching temperature and time resulted in significant (p < 0.05) decreases in PPO and POD activities. Compared to HWB, USB led to more effective drying by promoting texture softening, moisture diffusion, microstructure alterations, and microchannels formation, which significantly reduced energy consumption and improved the overall quality of the dried sample. Specifically, USB at 65 °C for 15 min improved water holding capacity and ABTS, while USB at 65 °C for 30 min improved color (more red and yellow), total phenolic content, total carotenoid content, and DPPH. Unfortunately, blanching process showed detrimental effects on the amino acid composition of dried samples. Overall, the development of thermoultrasound assisted blanching for sweet potatoes has the potential to revolutionize the processing and production of high-quality sweet potato products, while also improving the sustainability of food processing operations.

Yeast One-Hybrid Screening for Regulators of IbWD40 in Purple-Fleshed Sweet Potato (Ipomoea batatas [L] Lam.).

BACKGROUND: The transcription regulator IbWD40 is known to be involved in anthocyanin biosynthesis in purple-flesh sweet potato (Ipomoea batatas). However, little is known about the upstream transcription regulators on the promoter of IbWD40. METHODS: Yeast one-hybrid screening was performed on the storage roots of purple-fleshed sweet potato to identity upstream transcription regulators on the promoter of IbWD40. Luciferase reporter assays and Yeast one-hybrid assays were used to verify these upstream binding proteins interacted with the promoter. Real-time PCR was used to analyze the gene expression of upstream transcription regulators, transcription factors, and structural genes involved in anthocyanin biosynthesis in different root stages of purple-fleshed and white-fleshed sweet potato. RESULTS: IbERF1, IbERF10, IbEBF2, IbPDC, IbPGP19, IbUR5GT, IbDRM, IbPPA and IbERF73 were identified as candidate binding proteins for the promoter of IbWD40. Furthermore, IbERF1, IbERF10 and IbERF73 were identified as upstream transcription regulators on the promoter of IbWD40 involved in anthocyanin biosynthesis. CONCLUSIONS: IbERF1, IbERF10 and IbERF73 were identified as transcription regulators on the promoter of IbWD40, which is involved in the regulation of anthocyanin biosynthesis in purple-fleshed sweet potato.

Effects of crosslinking with sodium trimetaphosphate on structural, physicochemical, rheological and in vitro digestibility properties of purple sweet potato starch.

Purple sweet potato starch (PSPS) was modified using different amounts of sodium trimetaphosphate (0, 3-12%). Phosphorus content, crosslinking (CL), and substitution levels increased after modification. CL led to gradual agglomeration with each other through adhesion, compared to 0% STMP. X-ray diffraction did not change, but crystalline properties, swelling index, and peak viscosity increased, and solubility and glycaemic index decreased after crosslinking. Crosslinking increased, leading to a decrease of greater significance at 3% CL. Resistant starch was increased from 60.51 to 83.32%. G' and G'' values for crosslinking starch samples varied from 3086.00-5507.50 Pa and 513.92-800.30 Pa, respectively, after sweep test. The flow behavior index < 1 indicates that CL starch pastes are shear-thin. Positive and negative correlations were observed between gelatinized starch enthalpy and RS and between SDS and GI, respectively. The results lay the groundwork to comprehend the properties and relationships of CLPSPS and promote its possible use in foods.

Effects of sunflower pectin on thermal stability of purple sweet potato anthocyanins at different pH.

The present study aimed to examine the impact of sunflower pectin (SFP) on the thermal stability and antioxidant activity of purple sweet potato anthocyanins (PSPA) at varying pH levels. It was observed that the pH value significantly influenced the ability of pectin to protect anthocyanins from thermal degradation, which was found to be associated with the rate of binding between PSPA and SFP. The binding rate of PSPA-SFP was observed to be highest at pH 4.0, primarily due to the influence of electrostatic interaction and hydrogen bonding. Monoacylated anthocyanins exhibited a binding rate approximately 2-4 % higher than that of diacylated anthocyanins. The PSPA-SFP demonstrated its highest thermal stability at pH 4.0, with a corresponding half-life of 14.80 h at 100 °C. Molecular dynamics simulations indicated that pectin had a greater affinity for the flavylium cation and hemiketal form of anthocyanins. The antioxidant activity of anthocyanins in PSPA and PSPA-SFP increased with increasing pH, suggesting that anthocyanins at high pH had higher antioxidant activity than anthocyanins at low pH.

Diacylated anthocyanins from purple sweet potato (Ipomoeabatatas L.) attenuate hyperglycemia and hyperuricemia in mice induced by a high-fructose/high-fat diet. / ç´«è–¯åŒé °åŸºèŠ±è‰²è‹·å¯¹é«˜æžœç³–/é«˜è„‚è‚ªé¥®é£Ÿè¯±å¯¼çš„å°é¼ é«˜è¡€ç³–å’Œé«˜å°¿é ¸è¡€ç—‡çš„è°ƒèŠ‚ä½œç”¨.

Studies have shown that targeting xanthine oxidase (XO) can be a feasible treatment for fructose-induced hyperuricemia and hyperglycemia. This study aimed to evaluate the dual regulatory effects and molecular mechanisms of diacylated anthocyanins from purple sweet potato (diacylated AF-PSPs) on hyperglycemia and hyperuricemia induced by a high-fructose/high-fat diet. The body weight, organ index, serum biochemical indexes, and liver antioxidant indexes of mice were measured, and the kidneys were observed in pathological sections. The relative expression levels of messenger RNAs (mRNAs) of fructose metabolism pathway enzymes in kidney were detected by fluorescent real-time quantitative polymerase chain (qPCR) reaction technique, and the expression of renal transporter protein and inflammatory factor pathway protein was determined by immunohistochemistry (IHC) technique. Results showed that diacylated AF-PSPs alleviated hyperuricemia in mice, and that this effect might be related to the regulation of liver XO activity, lipid accumulation, and relevant renal transporters. Diacylated AF-PSPs reduced body weight and relieved lipid metabolism disorder, liver lipid accumulation, and liver oxidative stress, thereby enhancing insulin utilization and sensitivity, lowering blood sugar, and reducing hyperglycemia in mice. Also, diacylated AF-PSPs restored mRNA levels related to renal fructose metabolism, and reduced kidney injury and inflammation. This study provided experimental evidence for the mechanisms of dual regulation of blood glucose and uric acid (UA) by diacylated AF-PSPs and their utilization as functional foods in the management of metabolic syndrome.

Effect of cooking methods on metabolites of deep purple-fleshed sweetpotato.

The effects of different cooking methods on purple-fleshed sweetpotato (PFSP) metabolites were systematically explored, containing the changes of starch, soluble sugar, volatile organic compounds and non-target metabolites after steaming, boiling and baking. Compared to raw samples, the steamed samples showed the greatest changes in starch (degraded from 53.01% to 39.5%) and soluble sugar content (increased from 11.82% to 29.08%), while the baked samples showed insignificant changes in starch (51.06%). In total, 64 volatile organic compounds were identified in PFSP, with aldehydes decreasing and terpenes increasing after cooking. However, most of them were low in content and contributed weak aroma for PFSP. More importantly, 871 non-volatile metabolites were detected in PFSP, and 83.5% of which were well-preserved after cooking, while most of the changes were concentrated in phenylpropanoids, amino acids and carbohydrates. This study enriches the understanding of quality changes after PFSP cooking and helps consumers choose the right cooking method.

Effect of purple sweet potato-derived anthocyanins on heat stress response in Wenchang chickens and preliminary mechanism study.

This study was conducted to investigate the beneficial effect of purple sweet potato anthocyanins (PSPA) on growth performance, oxidative status, immune response, intestinal morphology, and intestinal flora homeostasis in heat-stressed Wenchang chickens. A total of 100 Wenchang chickens (50-day-old) were randomly assigned to 5 groups, including the thermoneutral environment (TN) group (26°C); high-temperature stressed (HS) group (33°C ± 1°C); low-dose PSPA treatment (L_HS) group (8 mg/kg body weight, 33°C ± 1°C); medium-dose PSPA treatment (M_HS) group and high-dose PSPA treatment (H_HS) group (16 mg/kg and 32 mg/kg body weight, respectively, 33°C ± 1°C). The results showed that PSPA reversed the adverse effects of heat stress on growth performance, meat quality, and carcass characteristics. And the effect was associated with the concentration of PSPA partially. Heat stress increased the serum lipids of Wenchang chickens. LDL-C, TG, TC, and FFA in the serum were significantly decreased, and HDL-C and LPS in the serum were increased by PSPA treatment. The digestive enzymes in duodenal chyme were significantly (P < 0.05) increased by PSPA treatment. And PSPA treatment significantly (P < 0.05) enhanced the redox status by improving antioxidant parameters (GSH-Px and SOD) and decreasing the MDA level in the serum and liver. Moreover, the level of inflammatory cytokines was significantly (P < 0.05) regulated by PSPA treatment compared to the HS group. The villus length and goblet cell numbers after PSPA treatment were significantly higher than HS group. Furthermore, PSPA also played protection on the intestine structure by decreasing the level of D-LA and DAO. 16S rRNA sequencing revealed the microbial composition was altered by PSPA, and Acetanaerobacterium and Oscillibacter were dominant in the H_HS group. Microbial functional prediction indicated that function pathways based on KEGG and metacyc database were regulated by PSPA, and intestinal flora correlated with metabolic function significantly. The spearman correlation analysis showed that Saccharibacteria and Clostridium_IV correlated with the serum lipids, antioxidant, and inflammatory cytokines. Collectively, these findings suggest that PSPA has a positive effect against heat stress in poultry.

Effect of modification by maltogenic amylase and branching enzyme on the structural and physicochemical properties of sweet potato starch.

Sweet potato starch (SPSt) was treated sequentially with the combination of maltogenic amylase (MA) and branching enzyme (BE) (MA â†’ BE) or BE and MA (BE→MA) to modify its structural and physicochemical properties. Following the MA â†’ BE and BE→MA modifications, the degree of branching was increased from 12.02 % to 44.06 %; whereas, the average chain length (ACL) decreased from 18.02 to 12.32. Fourier-transform infrared spectroscopy and digestive performance analysis indicated that the modifications reduced hydrogen bonds and increased resistant starch in SPSt. Rheological analysis revealed that the storage and loss moduli of the modified samples were lower than those of the control samples, except for starch treated with MA alone. X-ray diffraction measurements suggested that the re-crystallisation peak intensities of the enzyme-modified starches were lower than those of the untreated sample. The retrogradation resistance ability of the analysed samples followed the order: BE→MA-starches > MA â†’ BE-starches > untreated starch. The relationship between the crystallisation rate constant and short branched chains (DP6-9) was well described by linear regression. This study provides a theoretical foundation for retarding the retrogradation of starch, which can improve food quality and extend the shelf-life of enzymatically modified starchy foods.

Genetic diversity assessment and genome-wide association study reveal candidate genes associated with component traits in sweet potato (Ipomoea batatas (L.) Lam).

The Korean sweet potatoes were bred by various cultivars introduced from Japanese, American, Porto Rico, China, and Burundi. This issue enriched their genetic diversity but also resulted in a mixture of cultivars. For genotyping, we collected and sequenced 66 sweet potato germplasms from different localities around Korea, including 36 modern cultivars, 5 local cultivars, and 25 foreign cultivars. This identified 447.6 million trimmed reads and 324.8 million mapping reads and provided 39,424 single nucleotide polymorphisms (SNPs) markers. Phylogenetic clustering and population structure analysis distinctly classified these germplasms into 5 genetic groups, group 1, group 2, group 3, group 4, and group 5, containing 20, 15, 10, 7, and 14 accessions, respectively. Sixty-three significant SNPs were selected by genome-wide association for sugar composition-related traits (fructose, glucose, and total sugars), total starch, amylose content, and total carotenoid of the storage root. A total of 37 candidate genes encompassing these significant SNPs were identified, among which, 7 genes were annotated to involve in sugar and starch metabolism, including galactose metabolism (itf04g30630), starch and sucrose metabolism (itf03g13270, itf15g09320), carbohydrate metabolism (itf14g10250), carbohydrate and amino acid metabolism (itf12g19270), and amino sugar and nucleotide sugar metabolism (itf03g21950, itf15g04880). This results indicated that sugar and starch are important characteristics to determine the genetic diversity of sweet potatoes. These findings not only illustrate the importance of component traits to genotyping sweet potatoes but also explain an important reason resulting in genetic diversity of sweet potato.

Characterisation of acylated anthocyanins from red cabbage, purple sweet potato, and Tradescantia pallida leaves as natural food colourants by HPLC-DAD-ESI(+)-QTOF-MS/MS and ESI(+)-MSn analysis.

Anthocyanins in red cabbage, sweet potato, and Tradescantia pallida leaves were characterised. A total of 18 non-, mono-, and diacylated cyanidins was identified in red cabbage by high performance liquid chromatography-diode array detection coupled to high-resolution and multi-stage mass spectrometry. Sweet potato leaves contained 16 different cyanidin- and peonidin glycosides being predominantly mono- and diacylated. In T. pallida leaves, the tetra-acylated anthocyanin tradescantin prevailed. The large proportion of acylated anthocyanins resulted in a superior thermal stability during heating of aqueous model solutions (pH 3.0) coloured with red cabbage and purple sweet potato extracts as compared to that of a commercial Hibiscus-based food dye. However, their stability was still outperformed by that of the most stable Tradescantia extract. Comparing vis spectra from pH 1-10, the latter had an additional, uncommon absorption maximum at approx. 585 nm at slightly acidic to neutral pH values, yielding intensely red to purple colours.

Ozone exposure tunes the physicochemical properties of sweet potato starch by modifying its molecular structure.

Ozonation is an efficient method for improving the technical performance of some starches, but the feasibility of its use for sweet potato starch remains unknown. The effects of aqueous ozonation on the multi-scale structure and physicochemical properties of sweet potato starch were explored. Structurally, ozonation did not generate significant alterations at the granular level (size, morphology, lamellar structure, and long-range and short-range ordered structures), but led to tremendous changes at the molecular level, including converting hydroxyl groups to carbonyl and carboxyl groups and depolymerizing starch molecules. These structural changes resulted in prominent alternations in the technological performance of sweet potato starch, such as increases in water solubility and paste clarity and decreases in water absorption capacity, paste viscosity, and paste viscoelasticity. For these traits, their amplitudes of variation elevated when the ozonation time was extended and peaked at the longest ozonation time (60 min). The greatest changes in paste setback (30 min), gel hardness (30 min), and the puffing capacity of the dried starch gel (45 min) were observed at moderate ozonation times. In summary, aqueous ozonation is a new method for fabricating sweet potato starch with improved functionality.

Structural characterization and induction of tumor cell apoptosis of polysaccharide from purple sweet potato (Ipomoea batatas (L.) Lam).

The carbohydrate is the main ingredient of purple sweet potato. A polysaccharide, named PSP, was separated and purified from purple sweet potato by extraction with hot water, precipitation with ethanol, deproteinization with Sevag reagent and column chromatography with Sephadex G-100. The purity and structure were studied with HPLC, UV-Vis, GC-MS and NMR. The PSP is a neutral polysaccharide with Mw of 470 kDa. The monosaccharide composition of PSP contained D-xylose, d-glucose, D-galactose with ratio of 1.0: 8.3: 1.3. The backbone of PSP was composed of the residues of →6)-D-Glcp-(1 â†’ and →2, 6)-D-Glcp-(1→. The branches of PSP contained the residues of →3)-D-Galp-(1→, and D-Xylp-(1→. The antitumor activity in vitro of PSP was analyzed with HT-29 cells. And the SEM, AO staining, MDC staining and hoechst 33342 staining were performed to study the effect on apoptosis of HT-29 cells by PSP. The results revealed that the PSP can significantly inhibit the proliferation of HT-29 cells from induction apoptosis. The manuscript provided valuable knowledges on structural characteristics of the polysaccharides from purple sweet potato.

Effect of potassium intake on cadmium transporters and root cell wall biosynthesis in sweet potato.

Large areas of farmland soil in southern China are deficient in potassium (K) and are contaminated with cadmium (Cd). Previously, we suggested that the K supplementation could reduce Cd accumulation in sweet potatoes (Ipomoea batatas (L.) Lam). In the present study, we investigated the underlying physiological and molecular mechanisms. A hydroponic experiment with different K and Cd treatments was performed to compare the transcriptome profile and the cell wall structure in the roots of sweet potato using RNA sequencing, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The results showed that K supply inhibits the expressions of IRT1 and YSL3, which are responsible for root Cd uptake under Cd exposure. Furthermore, the expressions of COPT5 and Nramp3 were downregulated by K, which increased Cd retention in the root vacuoles. The upregulation of POD, CAD, INT1 and SUS by K contributed to lignin and cellulose biosynthesis and thickening of root xylem cell wall, which further reduced Cd translocation to the shoot. In addition, K affected the expressions of LHT, ACS, TPS and TPP associated with the production of ethylene and trehalose, which involved in plant resistance to Cd toxicity. In general, K application could decrease the uptake and translocation of Cd in sweet potatoes by regulating the expression of genes associated with Cd transporters and root cell wall components.

Studies on the interaction between homological proteins and anthocyanins from purple sweet potato (PSP): Structural characterization, binding mechanism and stability.

The protein-bound anthocyanin complexes are naturally existed in food systems by their spontaneous interaction. In this study, the interaction mechanism of homological proteins (p-PSP) and anthocyanins (FAC-PSP) was investigated to explore the binding characteristic of native protein-bound anthocyanins from purple sweet potato (p-BAC-PSP). The structural characterization, stability and anti-ultraviolet property of p-BAC-PSP were also evaluated. Results revealed that hydrophobic interaction is dominant binding force for forming p-BAC-PSP. The binding resulted in protein secondary structure changes with more ß-sheet and lower ß-turn, random coil structures. Fluorescence spectroscopy demonstrated that FAC-PSP quenched p-PSP fluorescence in a combination of static and dynamic mode (static dominant) with a binding constant of 105 L/mol reflecting strong affinity of FAC-PSP to p-PSP. Moreover, the complex form exhibited better protective effects on anthocyanins for pH, light, thermal stabilities and higher anti-ultraviolet activity. These findings further expanded the application of anthocyanins as stable, functional food and cosmetic ingredients.

Extraction, purification, structural characterization, and hepatoprotective effect of the polysaccharide from purple sweet potato.

BACKGROUND: Purple sweet potato Ipomoea batatas (L.) has long been used as a medicine and a food. It contains various bioactive substances such as polysaccharides, anthocyanins, and flavonoids. Purple sweet potato polysaccharides are known to have anti-oxidant, anti-tumor, and immunomodulatory functions. Nevertheless, studies on the structural characterization of purple sweet potato polysaccharides and their ability to prevent non-alcoholic fatty liver disease (NAFLD) have rarely been reported. RESULTS: A novel polysaccharide (PSPP-A) was extracted and isolated from purple sweet potato, and its structural characteristics and preventive effects on NAFLD were investigated. The results indicated that PSPP-A was composed of l-rhamnose, d-arabinose, d-galactose, d-glucose, and d-glucuronic acid with molar ratios of 1.89:8.45:1.95:1.13:1. Its molecular weight was 2.63 × 103 kDa. Methylation and nuclear magnetic resonance (NMR) analysis indicated that the glycosidic linkages were →3)-α-L-Araf-(1→, α-L-Araf-(1→, →2,4)-α-L-Rhap-(1→, 4-O-Me-ß-D-GlcAp-(1→, →4)-α-D-Glcp-(1→, →4)-ß-D-Galp-(1→, and →6)-ß-D-Galp-(1→. Scanning electron microscopy (SEM) indicated that the structure of PSPP-A was irregular. Subsequently, the protective effect of PSPP-A on NAFLD was investigated. The results indicated that bodyweight, liver index, and triglyceride (TG), total cholesterol (TC), aspartate transaminase (AST), and alanine transaminase (ALT) content were significantly reduced by intervention of purple sweet potato polysaccharide-A (PSPP-A) compared with the - high-fat diet group. Liver histopathological analysis indicated that PSPP-A attenuated irregular hepatocyte patterns and excessive lipid vacuoles. CONCLUSIONS: The novel polysaccharide, PSPP-A, mainly contains arabinose, which has certain preventive effects on NAFLD. This study provides a theoretical basis for further elucidating the hepatoprotective effect of purple sweet potatoes as a functional food. © 2022 Society of Chemical Industry.

Resistant starch from sweet potatoes: Recent advancements and applications in the food sector.

In tropical and subtropical areas, tuber and root crops are staple foods and a key source of energy. Sweet potato (SP) is currently regarded as one of the world's top ten foods because of its diverse sizes, shapes, color, and health benefits. The resistant starch (RS) content of SP is substantial. It is predicted to become the cheapest item in the food industry due to its extensive variety, food stability, emulsifier and fat substitution capabilities, and as filler. As a result, interest in SP-sourced RS has recently increased. Due to their unique nutritional and functional qualities, novelty has become a popular research focus in recent years. This review will summarize the current understanding of SP starch components and their impact on the technological and physicochemical properties of produced starch for commercial viability. The importance of sweet potato RS in addressing future RS demand sustainability is emphasized. SPs are a viable alternative to tubers as a sustainable raw material for RS production. It has an advantage over tubers because of its intrinsic nutritional value and climatic endurance. Thermal, chemical, and enzymatic treatments are effective RS manufacturing procedures. The adaptability of sweet potato RS allows for a wide range of food applications.