Potato Color Research Articles

Production of some Colored Potato Genotypes in Organic Culture

The purpose of this study was to identify the cultivars of potatoes with good production capacity and high nutritional value under ecologically culture conditions. The biological material consisted of five new potatoes cultivars: Brasovean, Carpatin, Cranberry Red, Montain Rose, Purple Majesty and Blue Congo. These new, highly pigmented varieties have yellow, pink or red peel and pulp, due to its high anthocyanin content. In order to achieve the objective, the productivity elements were determined: number of tubers and medium weight/plant, productivity as well as starches, carbohydrates, vitamin C content and antioxidant capacity. The obtained results were statistically interpreted by the analysis of variance, and the differences between genotypes were estimated by the threshold of significance at p≤0.05%. Cultivar Carpatin recorded the best production (32.7 t/ha) and Cranberry red and Montain Rose cultivars recorded the highest content in vitamin C (17.6 respectively 18.64 mg/100g f.m) and Blue Congo with highest antioxidant capacity (162.65 DPPH μMTE/100g).

Investigating the influence of novel drying methods on sweet potato (Ipomoea batatas L.): Kinetics, energy consumption, color, and microstructure

AbstractThis study investigated the drying kinetics, specific energy consumption (SEC), color, and microstructural changes of sweet potato (Ipomoea batatas L.) based on experimental set‐up of convective hot‐air drying (CHAD), infrared drying (IRD), and combined infrared and convective‐hot‐air drying (IR‐CHAD). The experiments were carried out at three air temperatures (50, 60 and 70 °C) and two IR intensities (1,100 and 1,400 W/m2) for sweet potato slices of 4 and 6 mm, respectively. The experimental results showed that the drying kinetics and mass transfer characteristic were significantly affected by drying air temperature, IR intensity, and thickness of the product. Combined IR‐CHAD provided a higher drying rate with the shortest drying time when compared with CHAD and IRD. The IRD resulted in the lowest SEC values. The combined IR‐CHAD resulted in 69.34–85.59% reduction in the SEC of CHAD. For combined IR‐CHAD, an increase in the IR intensity at each temperature and slice thickness caused a decrease in the total SEC value. Dried sweet potato slices using CHAD and IR1‐CHAD at intensity of 1,100 W/m2 showed the best color attributes. Combined IR‐CHAD proved to be a very efficient drying method for the drying sweet potato and can be used for both industrial and commercial purposes.Practical applicationsThe rising concern regarding a more efficient drying method has rapidly increased the demand for novel drying techniques that can be used to produce premium dried sweet potato. However, most of these novel drying methods have not been thoroughly investigated and technical comparison with the common conventional methods have not been widely reported. In this respect, this study has shown that the novel combined IR‐CHAD is a very promising drying method for the industrial drying of sweet potato. This drying method could reduce the over drying time by 63–74% and SEC by 85% when compared with drying using conventional CHAD method. The combined IR‐CHAD at a lower IR intensity of 1,100 W/m2 could also provide dried sweet potato of better quality. The will amount to a reduction of the overall production cost which adversely could affect the prices of the final quality products.

Effect of ultrasound pretreatment on iron fortification of potato using vacuum impregnation

In this study, the whole potato was fortified with iron by using vacuum impregnation (VI) with an ultrasound (US) pretreatment. The physicochemical properties of VI-processed potatoes were evaluated after a cooking process. The optimization of US pretreatment parameters was performed with respect to area fraction parameter, color, and texture and components leakage. The use of US with a lower frequency and a higher power intensity caused a higher ink impregnation, leakage of sugar content, and phenolic components after VI processing. The parameters of US have not a significant effect on color and texture of VI-processed potatoes. The obtained results indicated that VI and US–VI processes significantly enhanced the iron content about 137.5 and 210%, respectively. For fortified-cooked potatoes, the relative bioavailability of SunActive Fe was lower than the ferrous sulfate, but it had no undesirable effect on sensory evaluation, color parameters, and texture of fortified potatoes. Practical applications Food fortification with iron is a suitable strategy to control the iron deficiency. The ultrasound (US) pretreatment prior to vacuum impregnation (VI) leads to a higher iron impregnation. The US pretreatment has not significant effects on the color and textural properties of whole potatoes fortified by VI. SunActive Fe can be also considered as a suitable iron source to fortification of potato due to no undesirable effect on sensory properties, color parameters, and oxidative stability.

Purple sweet potato color attenuates high fat-induced neuroinflammation in mouse brain by inhibiting MAPK and NF-κB activation.

Purple sweet potato color (PSPC) is a natural anthocyanin pigment that is derived from purple sweet potato storage roots. PSPC possesses a variety of biological activities, including antioxidant, anti‑inflammatory and neuroprotective effects; however, the detailed effects of PSPC on high‑fat diet (HFD)‑induced neuroinflammation remain to be determined. The aim of the present study was to investigate whether PSPC has a protective role in HFD‑associated neuroinflammation in the mouse brain and to provide novel insight into the mechanisms of the action. C57BL 6J mice were maintained on a normal diet (10 kcal% fat), a HFD (60 kcal% fat), a HFD with PSPC (700mg/kg/day) or PSPC alone, which was administrated over 20weeks. Open field and step‑through tests were used to evaluate the effects of HFD and PSPC on mouse behavior and memory function. Western blotting and ELISA analyses were used to assess the expression of inflammatory cytokines and the activation of mitogen‑activated protein kinase and nuclear factor‑κB (NF‑κB). The results demonstrated that PSPC treatment was able to significantly improve the HFD‑induced impairment of mouse behavior and memory function, and suppressed the increase in body weight, fat content, hyperlipemia and the level of endotoxin. PSPC treatment also markedly decreased the expression of cyclooxygenase‑2, inducible nitric oxide synthase, tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6, and increased the level of IL‑10 in the HFD‑treated mouse brain. In addition, PSPC inhibited the HFD‑induced phosphorylation of extracellular signal‑regulated kinase (ERK), c‑Jun N‑terminal kinase (JNK) and p38, and the activation of NF‑κB. These findings indicated that PSPC treatment may alleviate HFD‑induced neuroinflammation in the mouse brain by inhibiting ERK, JNK, p38 and NF-κB activation.

Ultrasound-assisted osmotic process on quality of microwave vacuum drying sweet potato

ABSTRACTThe effects of pretreatment before microwave vacuum drying (MVD) on texture, color, expansion, rehydration, drying rate, microstructure, sensory evaluation, and other properties of sweet potato were investigated in this study. The pretreatment consisted in five processing conditions, using blanching; osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (US); ultrasound in distilled water before osmotic dehydration (US + OD), and ultrasound-assisted osmotic dehydration (USOD). Pretreatments of sweet potato before MVD have shown success in reducing drying time with US treatment relatively more effective regarding drying time than other treatments. Compared with other treatments, US showed the highest rehydration ratio values. The osmotic group pretreatment exhibited a pronounced effect on water loss and solid gain, improved the color, aroma, and taste of dried sweet potato, whereas sucrose impregnation resulted in a hard texture observed with OD sample. USOD samples had a higher expansion ratio, lower hardness and color difference values, appeared less cell damaged, and recorded better overall quality than the other samples. There was a slight difference between USOD and US + OD samples. Combining osmotic dehydration with ultrasound as a pretreatment can significantly accelerate the heat transfer rate, reducing the dried time accordingly and increasing energy efficiency.

FORMULASI DAN EVALUASI SEDIAAN LIP BALM DENGAN PEWARNA EKSTRAK UBI JALAR UNGU (Ipomoea batatas (L.) Lamk.)

Lip balm is a cosmetic preparation with the main components such as wax, fat, and oil from natural or synthesized extracts with the aim of preventing dryness of the lips by increasing lip moisture and protecting the adverse effects of the environment on the lips. The use of purple sweet potato as a dye is because purple sweet potato (Ipomoea batatas (L.) Lamk.) has an attractive color, the color of purple sweet potato is due to the presence of anthocyanin pigments which are derivatives of flavonoid compounds which are generally soluble in polar solvents. This study aims to formulate and evaluate lip balm preparations using purple sweet potato extract at concentrations of 3%, 6%, 9%, and without using purple sweet potato extract. This research is experimental research. Lip balm preparations were made by adding purple sweet potato extract with various concentrations (F1) 3%, (F2) 6%, (F3) 9%, and blank formula (F0) as the basis for lip balm preparations without purple sweet potato extract. Evaluation of the preparation includes homogeneity test, stability test, smear test, adhesion test, spreadability test, and pH test. The test results showed that purple sweet potato extract can be formulated in lip balm preparations that have a homogeneous composition, have good smearing power, good adhesion F0 (1 minute), F1 (1 minute 3 seconds), F2 (1 minute 8 seconds). seconds), F3 (1 minute 11 seconds), spreadability (5-5.7cm), pH test on all preparations showed a pH that was in accordance with the pH of the skin. And obtained formula 3 is the best formula.

Hyperspectral imaging for the determination of potato slice moisture content and chromaticity during the convective hot air drying process

Hyperspectral imaging (HSI) was utilised for the determination of moisture content of potato slices with three thicknesses (5 mm, 7 mm, 9 mm) at three drying temperatures (50 °C, 60 °C, 70 °C) during convective drying in a laboratory hot air dryer. The Page, thin-layer drying model was found better to explain the drying kinetics with a fitting accuracy of R2 (0.96–0.99) and lowest reduced Chi-square (0.00024–0.00090), Root mean square errors (RMSE) (0.014–0.026), and relative percentage error (1.5%–5.1%) under the used drying conditions. Spectral data were analysed using partial least squares regression (PLS) analysis, a multivariate calibration technique, alongside Monte Carlo Uninformative Variable Elimination (MCUVE-PLS) and competitive adaptive reweighted sampling (CARS-PLS). The feasibility of both moisture content and CIELAB prediction with a reduced wavelength set from the Visible near-infrared (VNIR) region (500–1000 nm) was investigated with these three models. The PLS model (R2 = 0.93–0.98, RMSE = 0.16–0.36 and the lowest number of optimal wavelengths = 6, for all drying conditions) was found suitable to implement for the moisture visualisation procedure. Potato chromaticity was also shown to be predictable during drying using a similar number of wavelengths, with PLS models for CIELAB a* performing well (R2 = 0.91–0.65, RMSE = 0.61–1.78). PLS Models for CIELAB b* more variably (R2 = 0.91–0.62, RMSE = 2.16–4.42) due to potato colour mainly varying along this axis. The current study showed that hyperspectral imaging was a useful tool for non-destructive measurement and visualisation of the moisture content and chromaticity during the drying process.

Effects of radio frequency assisted blanching on polyphenol oxidase, weight loss, texture, color and microstructure of potato

This paper is focused on the effects of radio frequency (RF) heating on the relative activity of polyphenol oxidase (PPO), weight loss, texture, color, and microstructure of potatoes. The results showed that pure mushroom PPO was almost completely inactivated at 80 °C by RF heating. The relative activity of potato PPO reduced to less than 10% with increasing temperature (25–85 °C). Enzyme extract showed the lowest PPO relative activity at 85 °C after RF treatment, followed by the potato cuboids and mashed potato, about 0.19 ± 0.017%, 3.24 ± 0.19%, and 3.54 ± 0.04%, respectively. Circular dichroism analysis indicated that RF heating changed the secondary structure of PPO, as α-helix content decreased. Both electrode gap and temperature had significant effect (P < .05) on weight loss, color, and texture of the potato cuboids. Microstructure analysis showed the changes of potato cell and starch during RF heating.

Analysis of Variation in Anthocyanin Composition in Korean Coloured Potato Cultivars by LC-DAD-ESI-MS and PLS-DA

Anthocyanin concentration and composition and the effect of steaming and baking on these were evaluated in tubers of Korean red- and purple-fleshed potato cultivars and breeding clones using liquid chromatography with diode array detection and electrospray ionization-mass spectrometry (LC-DAD-ESI-MS). Twenty-six anthocyanins were isolated, of which 24 were identified. Remarkably, five cis isomers were identified, of which four, viz., cis-petanin, cis-peonanin, petunidin 3-cis-caffeoylrutinoside-5-glucoside, and petunidin 3-cis-feruloylrutinoside-5-glucoside, are reported for the first time. Moreover, pelargonidin 3-p-coumaroylrutinoside-5-glucoside (pelanin), peonidin 3-p-coumaroylrutinoside-5-glucoside (peonanin) and petunidin 3-p-coumaroylrutinoside-5-glucoside (petanin) were identified as the principal anthocyanins. We found that the total anthocyanin content of coloured potatoes was decreased by steaming and baking compared with the raw state. In addition, we performed partial least square discriminant analysis (PLS-DA) to discriminate between the analyzed anthocyanins. Cis isomers seemed to play a vital role as a biomarker in the PLS-DA model based on the type of processing and colour of the tubers.

Effect of drying and grinding characteristics of colored potato (Solanum tuberosum L.) on tribology of mashed colored potato paste

ABSTRACTThe mouthfeel of mashed potato prepared with steamed purple flesh potato (SPFP) was investigated by measuring tribological and rheological characteristics. Mathematical models describing pre-processes such as drying and grinding associated with physical properties of mashed potato were also explored. The effect of drying temperature (60, 70, 80, and 90°C) on quality changes (moisture and anthocyanin content) of SPFP was successfully described (R2 > 0.9583). The sigmoid model was suitably applied to estimate particle sizes of dried SPFP during grinding (R2 > 0.9864). As the particle size of mashed SPFP increased, friction coefficient increased, and storage and loss modulus decreased. Taste, smoothness, and after-feel sensation were increased as particle sizes decreased, while appearance and odor showed no significant differences. To predict the sensory property using tribology and rheology, the specific conditions were successfully determined (R2 > 0.9926).

The Inhibitory Effects of Purple Sweet Potato Color on Hepatic Inflammation Is Associated with Restoration of NAD⁺ Levels and Attenuation of NLRP3 Inflammasome Activation in High-Fat-Diet-Treated Mice.

Purple sweet potato color (PSPC), a class of naturally occurring anthocyanins, exhibits beneficial effects on metabolic syndrome. Sustained inflammation plays a crucial role in the pathogenesis of metabolic syndrome. Here we explored the effects of PSPC on high-fat diet (HFD)-induced hepatic inflammation and the mechanisms underlying these effects. Mice were divided into four groups: Control group, HFD group, HFD + PSPC group, and PSPC group. PSPC was administered by daily oral gavage at doses of 700 mg/kg/day for 20 weeks. Nicotinamide riboside (NR) was used to increase NAD+ levels. Our results showed that PSPC effectively ameliorated obesity and liver injuries in HFD-fed mice. Moreover, PSPC notably blocked hepatic oxidative stress in HFD-treated mice. Furthermore, PSPC dramatically restored NAD+ level to abate endoplasmic reticulum stress (ER stress) in HFD-treated mouse livers, which was confirmed by NR treatment. Consequently, PSPC remarkably suppressed the nuclear factor-κB (NF-κB) p65 nuclear translocation and nucleotide oligomerization domain protein1/2 (NOD1/2) signaling in HFD-treated mouse livers. Thereby, PSPC markedly diminished the NLR family, pyrin domain containing 3 (NLRP3) inflammasome activation, ultimately lowering the expressions of inflammation-related genes in HFD-treated mouse livers. In summary, PSPC protected against HFD-induced hepatic inflammation by boosting NAD+ level to inhibit NLRP3 inflammasome activation.

Metabolite profiling of red and blue potatoes revealed cultivar and tissue specific patterns for anthocyanins and other polyphenols.

Metabolite profiling of tuber flesh and peel for selected colored potato varieties revealed cultivar and tissue specific profiles of anthocyanins and other polyphenols with variations in composition and concentration. Starchy tubers of Solanum tuberosum are a staple crop and food in many countries. Among cultivated potato varieties a huge biodiversity exists, including an increasing number of red and purple colored cultivars. This coloration relates to the accumulation of anthocyanins and is supposed to offer nutritional benefits possibly associated with the antioxidative capacity of anthocyanins. However, the anthocyanin composition and its relation to the overall polyphenol constitution in colored potato tubers have not been investigated closely. This study focuses on the phytochemical characterization of the phenolic composition of a variety of colored potato tubers, both for peel and flesh tissues. First, liquid chromatography (LC) separation coupled to UV and mass spectrometry (MS) detection of polyphenolic compounds of potato tubers from 57 cultivars was used to assign groups of potato cultivars differing in their anthocyanin and polyphenol profiles. Tissues from 19 selected cultivars were then analyzed by LC separation coupled to multiple reaction monitoring (MRM) to detect quantitative differences in anthocyanin and polyphenol composition. The measured intensities of 21 anthocyanins present in the analyzed potato cultivars and tissues could be correlated with the specific tuber coloration. Besides secondary metabolites well-known for potato tubers, the metabolic profiling led to the detection of two anthocyanins not described for potato tuber previously, which we tentatively annotated as pelargonidin feruloyl-xylosyl-glucosyl-galactoside and cyanidin 3-p-coumaroylrutinoside-5-glucoside. We detected significant correlations between some of the measured metabolites, as for example the negative correlation between the main anthocyanins of red and blue potato cultivars. Mainly hydroxylation and methylation patterns of the B-ring of dihydroflavonols, leading to the formation of specific anthocyanidin backbones, can be assigned to a distinct coloring of the potato cultivars and tuber tissues. However, basically the same glycosylation and acylation reactions occur regardless of the main anthocyanidin precursor present in the respective red and blue/purple tissue. Thus, the different anthocyanin profiles in red and blue potato cultivars likely relate to superior regulation of the expression and activities of hydroxylases and methyltransferases rather than to differences for downstream glycosyl- and acyltransferases. In this regard, the characterized potato cultivars represent a valuable resource for the molecular analysis of the genetic background and the regulation of anthocyanin side chain modification.

Attenuation of hepatic steatosis by purple sweet potato colour is associated with blocking Src/ERK/C/EBPβ signalling in high-fat-diet-treated mice.

Our previous work showed that purple sweet potato colour (PSPC), a class of naturally occurring anthocyanins, effectively improved hepatic glucose metabolic dysfunction in high-fat-diet (HFD)-treated mice. This study investigated the effects of PSPC on HFD-induced hepatic steatosis and the signalling events associated with these effects. Mice were divided into 4 groups: control group, HFD group, HFD+PSPC group, and PSPC group. PSPC was administered daily for 20 weeks at oral doses of 700 mg/(kg·day)-1). Our results showed that PSPC significantly improved obesity and related metabolic parameters, as well as liver injury in HFD-treated mice. Moreover, PSPC dramatically attenuated hepatic steatosis in HFD-treated mice. PSPC markedly prevented oxidative stress-mediated Src activation in HFD-treated mouse livers. Furthermore, PSPC feeding remarkably suppressed mitogen-activated protein kinase kinase/extracellular-signal-regulated kinase (MEK/ERK) signalling and consequent CCAAT/enhancer binding protein β (C/EBPβ) activation and restored AMPK activation in HFD-treated mouse livers, which was confirmed by U0126 treatment. Ultimately, PSPC feeding dramatically reduced protein expression of FAS and CD36 and the activation of ACC, and increased the protein expression of CPT1A in the livers of HFD-treated mice, indicating decreased lipogenesis and fatty acid uptake and enhanced fatty acid oxidation. In conclusion, PSPC exhibited beneficial effects on hepatic steatosis, which were associated with blocking Src and C/EBPβ activation.

Influence of ultrasound pretreatments on diffusion coefficients, texture and colour of osmodehydrated sweet potato (Ipomea batatas)

AbstractThe moisture and solute diffusivities, texture and colour of sweet potato pretreated in distilled water with ultrasound (UD), osmotic dehydration without ultrasound (OD) and osmotic dehydration with ultrasound (UOD) were investigated to determine the effects of ultrasound on osmodehydrated sweet potato. The moisture and solute diffusivities of all the pretreatments ranged from 2.89 to 4.95 × 10−10 and 1.17 to 1.67 × 10−10 m2 s−1, respectively. The moisture diffusivity of samples treated in UOD was significantly (P &lt; 0.05) higher than that of OD and UD by 30.82% and 41.62%, respectively. Compared to the fresh sample, the firmness of samples treated in OD and UOD was reduced by 83.53% and 92.47%, respectively. UD increased the brightness (L*) and reduced the redness (a*) of sweet potato, while UOD enhanced the yellowness (b*) and chroma (C*) of sweet potato. The sweet potato samples treated in UOD had the highest total colour difference (ΔE).

Sous Vide Processing as an Alternative to Common Cooking Treatments: Impact on the Starch Profile, Color, and Shear Force of Potato (Solanum tuberosum L.)

This study aimed to assess the effect of sous vide cooking on the total and resistant starch content, color, and shear force in three potato cultivars (Agria, Agata, and Carrera). Potato strips were also cooked by three common treatments (boiling, frying, and microwaving) to evaluate the differences between the methods. According to principal component analysis (PCA), sous vide-processed cv. Agria and Agata potato strips were grouped with boiled samples, in contrast, cv. Carrera sous vide samples were grouped with microwaved samples. Higher water losses were associated with microwaved potatoes due to the diffusion of water inside the tuber. In addition, a significant decrease in shear force was obtained after microwaving and sous vide cooking (p < 0.05) irrespective of the treatment strength. The three cultivars became less bright, and the intensity of the color decreased; however, variations in the cook value (C100, min) between treatments did not affect the lightness and hue angle. Regardless of the initial value of resistant starch and the intensity of the cooking process, all of the cultivars reached a final content of less than 5%. From our results, in-pack sterilization may be considered for application in the food industry as a technology that has a similar impact to conventional cooking treatments used on potato products.

Physicochemical and antioxidant capacity analysis of colored sweet potato genotypes: in natura and thermally processed

ABSTRACT: Sweet potato ( Ipomoea batatas (L.) Lam) is one of the most popular and ancient roots of Brazil and it can be consumed at different forms such as boiled, roasted or as sweets. Its cooking can lead to physicochemical transformations altering the nutritional properties. The objective of this study was to evaluate the physicochemical characteristics, bioactive compounds and antioxidant capacity of twelve sweet potato genotypes of varying pulp color in natura and roasted. Soluble solids, acidity, sugars, carotenoids, anthocyanins, phenolic compounds and antioxidant capacity were analyzed in the following sweet potatoes genotypes: cream pulp (Rubissol, Cuia, ILS03, ILS10, ILS12, ILS24 and ILS44); orange pulp (Amelia and Beauregard); and purple pulp (ILS56, ILS16 and ILS71). According to the results, it was observed a wide variation among the sweet potato genotypes for all analyzed parameters, in both preparation forms. The antioxidant capacity was a parameter with wide variation among genotypes, 210.29 to 7870.57µg trolox equivalent/g in in natura form and 673.26 to 17306.22µg trolox equivalent/g in roasted form. Soluble solids, acidity, sugars and bioactive compounds, with the exception of carotenoids, tended to be concentrated, also increases the total antioxidant capacity, in roasted sweet potatoes. In conclusion, genotype and the color of sweet potatoes were parameters that had an influence on its chemical composition. Cultivars such as Amelia and Beauregard stood out by the amounts of total soluble solids and carotenoids, respectively. The selections ILS 16 and ILS 56 are recommended as sources of anthocyanins. Thermal process influenced the concentration of antioxidant compounds and changed some physicochemical characteristics.

Fractionation, enzyme inhibitory and cellular antioxidant activity of bioactives from purple sweet potato (Ipomoea batatas).

Sweet potato (Ipomoea batatas L.) is mainly cultivated in Asia. The deep purple color of purple sweet potato (PSP) is due to the high content of acylated anthocyanins. In the present study, PSP-derived polyphenols were identified using HPLC-PDA and HPLC-ESI-MSn analyses. After concentration of the polyphenols from PSP, preparative separation into two fractions, designated anthocyanins (AF) and copigments (CF), was carried out using adsorptive membrane chromatography. In enzyme inhibitory assays, all PSP samples inhibited the enzymes α-amylase, α-glucosidase and xanthine oxidase. Additionally, the cell signaling cellular antioxidant properties of the PSP extracts were investigated in cultured cells. PSP induced the transcription factor Nrf2, which regulates the expression of genes encoding heme oxygenase 1 (Hmox1), glutamate-cysteine ligase catalytic subunit (Gclc) and paraoxonase 1 (PON1). Furthermore, PSP enhanced cellular glutathione concentrations and decreased lipid peroxidation in cultured hepatocytes. Overall, these results suggest that PSP extracts exhibit enzyme inhibitory and cellular antioxidant properties, especially PSP CF.

The Protective Effect of Antioxidant Enriched Fractions from Colored Potatoes Against Hepatotoxic Oxidative Stress in Cultured Hepatocytes and Mice

Herein, we prepared standardized antioxidant-enriched fractions from red (AFR) and purple (AFP) colored potatoes and evaluated their protective effects against hepatotoxicity induced by oxidative stress. The major compound contained in both AFR and AFP was 5-caffeoylquinic acid. Experiments in vitro showed that AFR and AFP protected against HepG2 cell death induced by tert-butyl hydroperoxide (t-BHP) as determined by cell viability assay. AFR and AFP recovered alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzyme activities, which increased by t-BHP treatment in HepG2 cells. AFR and AFP also inhibited the cleavage of PARP and caspase-3 in HepG2 cells. Moreover, in vivo experiments in mice showed that AFR and AFP protected against t-BHP-induced hepatotoxicity and recovered serum ALT and AST enzyme activities. AFR and AFP also rescued serum antioxidant enzyme activities, catalase and glutathione peroxidase, which were disturbed by t-BHP treatment. Our data clearly demonstrate that AFR and AFP protect against hepatic damage induced by oxidative stress. Practical Applications Colored potatoes contain plentiful amounts of antioxidant compounds that can be developed into dietary supplements for the improvement of human health. We prepared antioxidant-enriched fractions from red and purple colored potatoes (AFR and AFP, respectively) to be used as hepatoprotective agents. Based on chemical profiling analysis, we found that 5-caffeoylquinic acid can serve as a marker for the standardization of AFR and AFP as functional food materials. AFR and AFP strongly protected against oxidative stress and injury both in cultured hepatocytes and mice. AFR and AFP prevented the cell death of hepatocytes, and they also rescued hepatic damage markers ALT and AST both in cell and animal experiments. Generally, AFP showed higher hepatoprotective activity than AFR. Taken together, AFR and AFP may be promising candidates as functional foods for improving human liver function.

Texture and color analysis of freeze-dried potato (cv. Spunta) using instrumental and image analysis techniques

ABSTRACTMost typical approaches for measuring color and texture properties are time consuming. An image-based method was used to evaluate the texture and color in freeze-dried potatoes. Microstructure of cooked, cooked freeze-dried and rehydrated potatoes were analyzed by scanning electron microscopy. Texture properties were analyzed by a texture analyzer and image analysis. Color was determined with a spectrocolorimeter and a digital camera. Significant differences (p < 0.05) were obtained for cooked and cooked freeze-dried rehydrated potatoes. A linear trend was applied for instrumental and image features for texture and color values. Results showed that texture features of images, such as contrast, entropy, energy, and homogeneity (calculated from grey level co-occurrence matrix), showed correlations with instrumental texture features, such as hardness, adhesiveness, chewiness, cohesiveness, and resilience. Similar results were also obtained for color features. This study showed that image processing techniques could be applied as a useful tool to analyze quality in potatoes.

A combined hurdle approach of slightly acidic electrolyzed water simultaneous with ultrasound to inactivate Bacillus cereus on potato

Slightly acid electrolyzed water (SAcEW) and ultrasound (US) treatment have emerged as an environmental-friendly antimicrobial agent. However, SAcEW treatment alone shows low antimicrobial efficiency. Therefore, the aim of this study was to develop a hurdle approach that combined SAcEW and US to improve the antimicrobial effect against Bacillus cereus as well as inhibition of the growth on potato. US treatment under different conditions of dip times, acoustic energy densities (AED) and temperatures were conducted to obtain the optimal condition. Our findings demonstrate that 3 min of US with 400 W/L of AED at 40 °C treatment (US + 40 °C) significantly (p ≤ 0.05) reduced B. cereus population by 2.3 ± 0.1 log CFU/g with minimal change in the color of potato. In addition, 3 min of SAcEW (pH, 5.3–5.5; ORP, 958–981 mV; ACC, 28–30 mg/L) simultaneous with US+40 °C treatment (SAcEW + US+40 °C) an approximately 3.0 log CFU/g reduction in B. cereus. Furthermore, SAcEW + US+40 °C treatment efficiently extended lag time of B. cereus by 0.2–10.5 hrs, reduced that of specific growth rate by 0.01–0.23 log CFU/h during storage at different temperatures from 5 to 35 °C. Therefore, this combined hurdle technology is capable of improving microbial safety of potato during storage and distribution.