Sweet Potato Anthocyanins Research Articles

Study on the Stability and Application of Anthocyanin from Purple Sweet Potato

The purple sweet potato anthocyanin was extracted by ethanol extraction, the stability of purple sweet potato anthocyanin was investigated in this paper, the purple sweet potato anthocyanin was water-soluble pigment, it had a strong resistance of heat and the best stability of anthocyanin was kept from light. Food preservatives had no significant effect on the stability of purple sweet potato anthocyanins; glucose and sucrose had a certain color-protecting effect on purple sweet potato anthocyanin; Vc had effects on purple sweet potato anthocyanin obviously; H2O2, Cu2+, Fe2+ had a greater impact on the stability of purple sweet potato anthocyanin. The solution of anthocyanin would become turbid with the effect of Cu2+and Fe2+.

Effect of Purple Variety Sweet Potato (Ipomoea batatas L.) Anthocyanin on Expression of Estrogen Receptor-Α and Endometrium Thickness on Uterus of Female White Rats (Rattus norvegicus) Exposed to Cigarette Smoke

Cigarette smoke contains around 4000 chemical substances including free radicals and carcinogens, which are xenobiotic agents in the body, affecting the reproductive system. Purple sweet potatoes contain the color pigment anthocyanin. The purple color pigment (anthocyanin) in purple sweet potatoes is a beneficial antioxidant because it can react with free radicals that can cause damage in the body. The goal of the research was to understand the effects of purple variety sweet potato (Ipomoea Batatas L) anthocyanin on the expression of estrogen receptor-α in the endometrium and endometrium thickness on white rats (Rattus norvegicus) exposed to cigarette smoke. The White rats used for the 5 groups were 30 white rats. Exposure to cigarette smoke was given at a rate of 2 sticks/day (each cigarette ± 4 minutes), for 8 weeks after the rats were found to be in the proestrus phase. Endometrium thickness was examined and measured using a Dot slide Olympus XC 10 light microscope and the Olyvia software. Expression of ER-α in the endometrium was measured by using the antibody ER-α (C-311) SC-787 and the immunohistochemistry and calculated by the Immunoratio software. Data were analyzed with the Shapiro-Wilk’s test, t-test and one-way ANOVA (F test). It was found that the average value of ER-α expression in the endometrium for the treatment group given purple variety sweet potato anthocyanin of a dose of 40 mg/Kg BW (15.51 ± 2.65) could increase ER-α expression in the endometrium of female white rats exposed to cigarette smoke. The average value of endometrium thickness for the treatment group given purple variety sweet potato anthocyanin at a dose of 40 mg/Kg BW (152.51±9.59 µm) showed an increase in the endometrium thickness of female white rats exposed to cigarette smoke. The dose of purple variety sweet potato anthocyanin that could increase ER-α expression in the endometrium and endometrium thickness of rats exposed to cigarette smoke was a dose of 40 mg/Kg BW. The higher the dose of purple variety sweet potato anthocyanin, the greater the effect on the prevention of the reduction of estrogen receptor-α expression and the prevention of the reduction of endometrium thickness on female white rats exposed to cigarette smoke.

Antioxidant and prebiotic activity of five peonidin-based anthocyanins extracted from purple sweet potato (Ipomoea batatas (L.) Lam.)

Twelve kinds of anthocyanins from the Chinese purple sweet potato cultivar (Ipomoea batatas (L.) Lam.) were extracted and identified using LC-MS/MS, which had a high content of peonidin-based anthocyanins. Five peonidin-based anthocyanin monomers (P1, P2, P3, P4 and P5) were isolated by preparative liquid chromatography with structural analyses using an Impact II Q-TOF MS/MS. Then, the functional properties of the anthocyanin monomers, such as the antioxidant activities, proliferative effects on probiotics, and their inhibition on harmful bacteria in vitro, were investigated. The peonidin-based components in purple sweet potato anthocyanins (PSPAs) showed good properties regarding scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and superoxide anions, and had good potential in reducing the total power activity and Fe2+ chelating ability. While the order of the antioxidant abilities was as follows: P4 > P5 > P3 > P2 > P1 > PSPAs. Microbial cultivations showed that P1, P2, P3, P4, P5 and PSPAs could induce the proliferation of Bifidobacterium bifidum, Bifidobacterium adolescentis, Bifidobacterium infantis and Lactobacillus acidophilus, and they inhibited the growth of Staphylococcus aureus and Salmonella typhimurium, suggesting the anthocyanins might have prebiotic-like activity through the modulation of the intestinal microbiota. Our results indicate that peonidin-based anthocyanins could be further utilized in health foods and pharmaceutical developments.

Effects of low acyl and high acyl gellan gum on the thermal stability of purple sweet potato anthocyanins in the presence of ascorbic acid

This study investigated the different effects of low acyl (LA) and high acyl (HA) gellan gum on the thermal stability of anthocyanin-containing model beverage systems in the presence of ascorbic acid. The addition of gellan gum, especially HA, resulted in higher absorbance values, which suggested higher anthocyanin stability during heat treatment. The thermal stability of each anthocyanin was significantly improved by the addition of gellan gum (P < 0.05). Moreover, diacylated anthocyanins exhibited higher heat resistance than monoacylated anthocyanins. The molecular dynamics simulations revealed that the improvement in the anthocyanin stability following the addition of gellan gum was due to the binding between the gellan gum and the anthocyanins. HA was found to have stronger interactions with the anthocyanins than LA, which was attributed to the increased steric hinderance and flexibility caused by the acyl groups. In summary, we revealed that gellan gum can potentially be used to enhance the thermal stability of anthocyanins in beverages and identified the important role of the acyl groups of gellan gum in stabilizing the anthocyanins. These findings will broaden the applications of gellan gum and improve the popularity of anthocyanin-containing beverages.

The influence and mechanisms of purple sweet potato anthocyanins on the growth of bladder cancer BIU87 cell

Objective: To observe the effect of purple sweet potato anthocyanins on the proliferation of bladder cancer cell line BIU87 and to investigate the molecular mechanisms. Methods: Bladder cancer BIU87 cells were cultured and exposed to anthocyanins at the different concentrations of 100, 200, 400, and 800 μg/ml respectively. The growth inhibition of anthocyanins on BIU87 cells were evaluated by morphometry and cell counting kit-8 (CCK-8) assay, and the cell apoptosis rate was detected by Flow cytometry (FCM). Results: Morphometry showed that the number of BIU87 cells decreased, the volume shrank, the intercellular space enlarged, the ability of cell adherence weakened, and the cell shape changed when the concentration of anthocyanins increased. CCK-8 assay showed that when 100, 200, 400, 800 μg/ml anthocyanins treated BIU87 cells for 48 h, the absorbance was 24 ± 0.07, 1.15 ± 0.11, 0.90 ± 0.08, 0.56 ± 0.09, respectively. Compared with the control group, anthocyanins-treated groups significantly inhibited the proliferation of BIU87 cells (P<0.05). FCM test showed that after treatment with different doses of anthocyanins, the apoptosis rate was 7.31%, 11.11%, 25.96%, 36.28%, respectively, and with the concentration of anthocyanins being higher, the apoptosis rate of BIU87 cells was being higher. Conclusion: Purple sweet potato anthocyanins can inhibit the growth of bladder cancer BIU87 cells through inducing cell apoptosis in a dose-dependent manner.

彩色马铃薯StMyb-like基因克隆表达分析与干涉载体构建

彩色马铃薯中富含花色苷，是天然抗氧化物质来源之一。本研究从彩色马铃薯“黑金刚”中克隆了与花色苷合成相关的调控基因，其编码产物且与马铃薯R2R3-MYB转录因子高度同源，被命名为StMyb-like基因。该基因全长798 bp，编码个265个氨基酸，分子量为30.23 kD。通过半定量RT-PCR分析StMyb-like基因的表达，发现该基因在根和茎中表达量很低，而在富花色苷的薯肉、薯皮、芽和叶片中表达量比较高。为了研究彩色马铃薯StMyb-like基因的功能，利用DNA重组技术构建该基因的植物RNA干涉载体pART-MybRNAi，为后续研究该基因可能所参与的生命活动提供了基础。 Color potato is rich in anthocyanins, which is one of the natural antioxidants. In this study, one gene related to anthocyanin synthesis was cloned from the color potato “Black King Kong”, and this gene encoding protein is highly homologous to transcription factor R2R3-MYB, and named as StMyb-like. The whole length of this gene is 798 bp, which encodes a 265 amino acid, with a molecular weight of 30.23 kD. The expression of StMyb-like gene was analyzed by semi quantitative RT-PCR. It was found that the expression level of the gene in roots and stems was very low, but the expression level of anthocyanin in sweet potato, potato skin, buds and leaves was relatively high. In order to study the function of StMyb-like gene in color potato, the pART-MybRNAi interference vector was constructed by using DNA recombination technology, which provides a basis for further study of the possible life activities of the gene.

Caco-2 cell transport of purple sweet potato anthocyanins-phospholipids complex.

In this study, the role of phospholipids in transepithelial transport and the impact on the antioxidant activity of purple sweet potato anthocyanins (PSPAs) was evaluated. PSPAs were purified by column chromatography, and then PSPAs-phospholipids complex (PSPAs-PC) was prepared. In antioxidant assay in vitro, PSPAs-PC exhibited potential antioxidant activity; meanwhile, it exhibited relatively higher stability in mimic gastrointestinal digestion conditions. The inhibitory effect of PSPAs-PC on the oxidation of soybean oil was significantly higher after 15days storage. The presence of phospholipids increased the transepithelial transport of PSPAs; its apparent permeability coefficient (Papp) was higher, while its efflux ratio was lower than PSPAs. Based on the above results, it clearly displays the potential of phospholipids in the promotion of intestinal transport of PSPAs, and further studies are needed to explore the in-depth mechanism of the bioavailability promotion effect of phospholipids.

The effect and evidence of ethanol content on the stability of anthocyanins from purple‐fleshed sweet potato

This study aimed to evaluate and understand the water–ethanol system effect on the stability of purple-fleshed sweet potato anthocyanins (PSPa). The stability of the PSPa in the model ethanol–water solutions (0–80%, vol/vol, pH 3.5) during storage (60 hr) at room temperature was monitored by UV-vis. The frontier molecular orbital theory was used to interpret the hydration reaction rate of the PSPa in both ethanol–water and aqueous solutions. In all of the model ethanol–water solutions, the degradation of the PSPa followed first-order kinetics during storage, and the degradation rates increased with increased ethanol concentration. Theory calculation results showed that an increase in ethanol concentration decreased the LUMO energy of anthocyanins, and accelerated nucleophilic attack from water, thus, resulting in lower stability. These findings could provide valuable evidence of the solvent effect on the stability of anthocyanins. Practical applications Fruit wines that contain anthocyanins are among the common alcoholic beverages. The stability of the anthocyanins is responsible for wine quality and may also affect the nutritional properties. Thus, investigating the effect of ethanol on the stability of anthocyanins is particularly valuable. The results of this research have important implications for the models developed so far to explain the degradation mechanism of anthocyanins in different media. In this context, examining the effect of different media on the degradation of anthocyanins would be useful to provide improved anthocyanin ability in the food and beverage industry.

Profiling of anthocyanins in transgenic purple-fleshed sweet potatoes by HPLC-MS/MS.

Anthocyanins in purple-fleshed sweet potato (PSP) are beneficial to human health. The leaf color (Lc) gene is a transcription factor involved in regulating anthocyanin biosynthesis. The anthocyanin profiles of wild-type PSP of Ayamurasaki and its three Lc-transgenic lines were investigated by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). In vitro antioxidant activities of wild-type and Lc-transgenic lines, including reducing power activity, DPPH radical scavenging activity, hydroxyl radical scavenging activity, linoleic acid autoxidation inhibition activity, ABTS free radical scavenging activity and oxygen radical absorbance capacity activity, were measured. The results showed that the total anthocyanin contents increased 1.5-1.9 times in three transgenic lines compared with that in wild-type PSP. Seventeen anthocyanins were found in wild-type PSP, while 19 in Lc-transgenic lines including cyanidin-based, peonidin-based and pelargonidin-based anthocyanins. Three pelargonidin-based anthocyanins were detected in three Lc-transgenic lines. Among them, the relative contents of cyanidin-based and pelargonidin-based anthocyanins increased 1.9-2.0 and 3.4-4.5 times respectively, while peonidin-based anthocyanins decreased 1.8-1.9 times in Lc-transgenic lines, compared with wild-type PSP. PSP from wild-type Ayamurasaki and three Lc-transgenic lines exhibited potent antioxidant activities, whereas there was no distinct difference among them. The transgene Lc significantly increased the content of total anthocyanins and remarkably changed the anthocyanin profiles in Ayamurasaki. Such novel and high content of anthocyanins obtained in the Lc-transgenic lines with potent antioxidant activities may provide unique functional products with potential helpful for human health. © 2017 Society of Chemical Industry.

Anthocyanins from purple sweet potato (Ipomoea batatas (L.) Lam.) and their color modulation by the addition of phenolic acids and food-grade phenolic plant extracts

Anthocyanin profiles and contents of three purple sweet potato provenances were investigated by HPLC-DAD-MSn. In contrast to widely uniform profiles, the contents of total (558–2477mg/100gDM) and individual anthocyanins varied widely. Furthermore, quantitative and qualitative effects of intermolecular co-pigmentation were studied by adding chlorogenic and rosmarinic acids, and food-grade phenolic apple and rosemary extracts at various dosages to a diluted purple sweet potato concentrate at pH 0.9, 2.6, 3.6, and 4.6. Addition of co-pigments generally increased pKH estimate-values of anthocyanins from 3.28 (without co-pigments) to up to 4.71, thus substantially broadening the pH range wherein colored forms prevail. The most pronounced hyperchromic shift by up to +50.5% at the absorption maximum was observed at pH 4.6. Simply by blending the co-pigments with purple sweet potato anthocyanins at pH-values ranging from 2.6 to 4.6, purplish-blue, light pink, magenta, brick-red, and intense red hues were accessible as expressed by CIE-L∗a∗b∗ color values.

Characterization of Anthocyanins in Sweetpotato leaves

As phytochemical‐enriched edible greens, sweetpotato (Ipomoea batatas L.) leaves have become popular due to potential health benefits. However, the phytochemical contents in sweetpotato leaves and their subsequent change over harvest stages and growth condition are mostly unknown. In this study we determined the anthocyanin profile and content in leaves of four sweetpotato cultivars (Bonita, Beauregard, Murasaki, and P40). Fourteen anthocyanins, including one newly discovered, were identified by HPLC‐MS/MS. The most abundant was cyanidin 3‐caffeoyl‐p‐hydroxybenzoyl sophoroside‐5‐glucoside, which comprised up to 20% of the total anthocyanins. Of the young leaves (1st and 2nd slip cuttings), Bonita contained the highest anthocyanin content followed by P40. Of the mature leaves (vine stage), Beauregard had the greatest anthocyanin (391 mg/kg DW) and total phenolic (52 GAE/g DW) content. It should be noted that the lowest anthocyanin and total phenolic content of shoots were found in P40, while tubers of P40 contain the highest content of each. Furthermore, the increase in leaf anthocyanin content over the growth stages that was observed in three of the cultivars was absent in P40. No significant difference of anthocyanin content was found in Beauregard leaves grown in the high tunnels or open field.Support or Funding Informationsupported by USDA Cooperative KS511‐1001903

TiO2 Nanostructure Synthesized by Sol-Gel for Dye Sensitized Solar Cells as Renewable Energy Source

The use of renewable materials as a constituent of a smart alternative energy such as the use of natural dyes for light harvesting needs to be developed. Synthesis of anatase titanium dioxide (TiO2) and fabrication Dye-Sensitized Solar Cell (DSSC) using dye-based of anthocyanin from purple sweet potato (Ipomoea batatas L.) as a photosensitizer had been done. Synthesis TiO2 through sol-gel process with the addition of triblock copolymer Pluronic F127 template was controlled at pH 3 whereas calcination was carried out at a temperature of 500 °C, 550 °C and 600 °C. The obtained TiO2 were analyzed by XRD, SAA, and SEM. The conclusion is anatase TiO2 obtained until annealing up to 600 °C. Self-assembly Pluronic F127 triblock copolymer capable of restraining the growth of TiO2 crystals. Retention growth of TiO2 mesoporous produces material character that can be used as builders photoanode DSSC with natural sensitizer anthocyanin from purple sweet potatoes. Based on the analysis of X-ray diffraction patterns and surface area analyser, the higher the calcination temperature the greater the size of the anatase crystals is obtained, however, the smaller its surface area. Purple sweet potato anthocyanin’s dyed on to TiO2 was obtained a good enough performance for DSSC’s and gain the optimum performance from DSSC’s system built with mesoporous TiO2 annealed 550 °C using flavylium form anthocyanin.

A Modified Method for the Determination of Acylated Anthocyanins in Purple-fleshed Sweet Potato (&lt;i&gt;Ipomoea batatas&lt;/i&gt; (L).) Tubers by High-performance Liquid Chromatography with Visible Absorption

A Modified Method for the Determination of Acylated Anthocyanins in Purple-fleshed Sweet Potato (&lt;i&gt;Ipomoea batatas&lt;/i&gt; (L).) Tubers by High-performance Liquid Chromatography with Visible Absorption

Characterization and hepatoprotective activity of anthocyanins from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8)

The hepatoprotective activity of anthocyanin-rich purple sweet potato extract (APSPE) was demonstrated. Sixty mice were randomly divided into six groups: control group [without carbon tetrachloride (CCl4) or APSPE]; model group (with CCl4 only); positive control group (50 mg/kg body weight silymarin); low-dose group (100 mg/kg body weight APSPE); medium-dose group (200 mg/kg body weight APSPE); and high-dose group (400 mg/kg body weight APSPE). After 10 days intragastric administration of the respective supplements, the mice in all groups except control were injected intraperitoneally with CCl4 (0.15% in arachis oil, 10 mL/kg body weight, intravenous). Twelve hours after CCl4 injection, the mice were measured in terms of liver index, levels of aspartate aminotransferase and alanine aminotransferase in serum, as well as glutathione, superoxide dismutase, and malondialdehyde in liver homogenate. Additionally, the livers of mice were stained with hematoxylin and eosin and sectioned for observation. Nineteen purple sweet potato anthocyanins were identified from the purple sweet potato cultivar Eshu No. 8 and analyzed by liquid chromatography– electrospray ionization–tandem mass spectrometry. Peonidin 3-coumaryl-p-hydroxybenzoyl sophoroside-5-glucoside was first identified in purple sweet potato. The results showed that anthocyanins in Eshu No. 8 had good hepatoprotective activity.

Synthesis of maltodextrin-grafted-cinnamic acid and evaluation on its ability to stabilize anthocyanins via microencapsulation

In this work, maltodextrin-grafted-cinnamic acid (MD-g-CA) was synthesised and used as wall material to improve the stability of purple sweet potato anthocyanins (PSPa) via microencapsualtion. MD-g-CA was prepared through esterification in a two-step convenient synthesis procedure and characterised using infra-red (IR) spectroscopy. The IR data indicated the typical ester carbonyl stretching at around 1721 cm−1. Moreover, MD-g-CA could give about 40% inhibition of DPPH radical and present excellent UV-absorption, which were notably better than that of native MD. Maltodextrin (MD) and MD-g-CA were used to prepare PSPa microcapsules by spray drying. The stability of PSPa was evaluated by UV-Vis analysis. The microcapsules produced by MD-g-CA showed a spheres-like appearance with some cracks. Storage tests revealed that the degradation rate of PSPa embedded by MD-g-CA was much lower than that of free PSPa under the same condition. Thus, MD-g-CA could be used as an effective wall material to improve stability of anthocyanins.

Purple Sweet Potato Anthocyanin Inhibits the Proliferation of Human Retinal Pigment Epithelial Cell by Blocking Cell Cycle and Inducing Apoptosis

Purple Sweet Potato Anthocyanin (PSPA), a class of naturally occurring anthocyanins derived from purple sweet potato storage roots, possesses unique color and multiple bioactivities. This study investigated the anti-proliferative effect of PSPA in human Retinal Pigment Epithelial (RPE) cells, the proliferation of which accounts for Proliferative Vitreoretinopathy (PVR). Blueberry Anthocyanin (BBA) was used as a contrast. PSPA and BBA inhibited RPE proliferation time-and dose-dependently through blocking the cell cycle in G0/G1 phase and inducing apoptosis via ROS accumulation, DNA damage and caspase 3/7 activation. Meanwhile, PSPA showed stronger potential than BBA in inhibiting RPE growth. Hence, we highlighted the importance of dietary supplementation of anthocyanins in PVR prevention and the application of PSPA in health industry.

Purple sweet potato anthocyanin attenuates fat-induced mortality in Drosophila melanogaster

A high fat diet induces the accumulation of lipid hydroperoxides (LPO), accelerates the ageing process and causes a greater mortality in Drosophila melanogaster. Purple sweet potato is rich in antioxidant anthocyanin. The purpose of the present study was to examine if supplementation of purple sweet potato anthocyanin (PSPA) could reduce the mortality of fruit flies fed a high-fat diet. Results showed that the mean lifespan of fruit flies was shortened from 56 to 35days in a dose-dependent manner when lard in the diet increased from 0% to 20%. PSPA supplementation partially attenuated the lard-induced mortality. The maximum lifespan and 50% survival time were 49 and 27days, respectively, for the 10% lard control flies, in contrast, these parameters increased to 57 and 30days in the PSPA-supplemented fruit flies. Similarly, addition of lard into diet increased the total body LPO, while addition of PSPA partially attenuated its increase. Real-time PCR analysis indicated that PSPA-supplemented diet significantly up-regulated the mRNA of superoxide dismutase (SOD), catalase (CAT) and Rpn11, compared with the control lard diet. The western blot analysis also demonstrated that PSPA supplementation was associated with up-regulation protein mass of SOD1, SOD2, and CAT. In addition, PSPA supplementation could restore the climbing ability of fruit flies fed a 10% lard diet. We could conclude that the lifespan-prolonging activity of PSPA was potentially mediated by modulating the genes of SOD, CAT and Rpn11.

The Modulatory Effect of Anthocyanins from Purple Sweet Potato on Human Intestinal Microbiota in Vitro

In order to investigate the modulatory effect of purple sweet potato anthocyanins (PSPAs) on human intestinal microbiota, PSPAs were prepared by column chromatography and their influence on intestinal microbiota was analyzed by monitoring the bacterial populations and analyzing short-chain fatty acid (SCFA) concentrations at different time points. The numbers (log10 cell/mL) of Bifidobacterium and Lactobacillus/Enterococcus spp., Bacteroides-Prevotella, Clostridium histolyticum, and total bacteria after 24 h of culture in anaerobic fermentation broth containing PSPAs were 8.44 ± 0.02, 8.30 ± 0.01, 7.80 ± 0.03, 7.60 ± 0.03, and 9.00 ± 0.02, respectively, compared with 8.21 ± 0.03, 8.12 ± 0.02, 7.95 ± 0.02, 7.77 ± 0.02, and 9.01 ± 0.03, respectively, in the controls. The results showed that PSPAs induced the proliferation of Bifidobacterium and Lactobacillus/Enterococcus spp., inhibited the growth of Bacteroides-Prevotella and Clostridium histolyticum, and did not affect the total bacteria number. Total SCFA concentrations in the cultures with PSPAs were significantly higher than in the controls (P < 0.05). Moreover, during the fermentation, the PSPAs were partially fragmented to phenolic acids, which may exert a better effect on intestinal microecology, suggesting that PSPAs may have prebiotic-like activity by generating SCFAs and modulating the intestinal microbiota, contributing to improvements in human health.

Copigmentation effects and thermal degradation kinetics of purple sweet potato anthocyanins with metal ions and sugars

The copigmentation effects of purple sweet potato anthocyanins (PSPAs) with metal ions and sugars were investigated in model solutions at pH 4. The thermal stability of PSPAs was also explored in the presence of sugars and 5-hydroxymethylfurfural (5-HMF). Copigmentation are characterized by hyperchromic effect and bathochromic shift. The hyperchromic effect of Fe3+ reached 25.15 % even at a very low concentration 0.005 mol L−1, while the values of the other metal ions at 0.05 mol L−1 were ranked in the following ascending order: K+ < Ca2+ < Mg2+ < Zn2+ < Cu2+ < Fe2+ < Al3+. The bathochromic shift was not observed in all sugar reaction solutions; glucose showed the highest values of hyperchromic effect at the concentration range 150–300 g L−1, followed by fructose and sucrose; konjac glucomannan showed the highest effect even at a much lower concentration among the macromolecular sugars. Especially, the konjac glucomannan exhibited a much better color enhancement than glucose. Small molecular sugars accelerated the thermal degradation of PSPAs, whereas macromolecular sugars showed a protective effect particularly at high temperatures. Moreover, 5-HMF resulted in the deterioration of the thermal stability of PSPAs and was suggested to be an important labile factor for copigmented PSPA solutions.

Effects of deodorization on the physicochemical index and volatile compounds of purple sweet potato anthocyanins (PSPAs)

Abstract To produce high quality purple sweet potato anthocaynins (PSPAs) extract, a deodorization process was developed and its effects on the physicochemical index including total anthocyanins, total sugar and protein, soluble solids, color values, degradation index (DI), brown index (BI) and clarity were investigated. The product sensory quality was also evaluated. The volatile compounds were analysed by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC/MS). The results indicated that using AB-8 macroporous resin purification coupled with chitosan adsorption could be an effective method in deodorization of the anthocyanin crude extract from purple sweet potato. Some byproducts in the anthocyanin crude extracts, such as sugars and proteins, had been removed by about 85% and 76% respectively. Compared with the raw anthocyanin extract, the volatile substances in the final product of PSPAs were changed and the unpleasant characteristic odors, such as some alcohols, aldehydes, organic acids and alkanes, were decreased. However, the product yield was also decreased by about 26% after the deodorization process.