Nutritional composition of freshly harvested and stored Latvian potato (Solanum tuberosum L.) varieties depending on traditional cooking methods

The information about nutritional composition of potatoes at both the ingredient and recipe levels in the Food Composition Data Base (FCDB) of Latvia is insufficient. Therefore, the aim of this research was to determine the nutritional composition and energy content of potatoes prepared by traditional cooking methods before and after storage. Five Latvian potato varieties were selected: Lenora, Brasla, Imanta, Zile and Madara. A two-year research was conducted during two periods: just after harvesting (2007, 2008) and after six months of storage (2008, 2009). The following cooking methods were used: shallow frying (150 ± 5 °C); deep-fat frying (180 ± 5 °C) and roasting (210 ± 5 °C). The weight of the potatoes was recorded before and after frying along with the time and temperature during frying. Chemical analyses were performed to determine the content of reducing sugars, starch, fructose, glucose, sucrose, fibre, fat, protein, moisture, vitamin C and amino acids. The content of the analyzed nutrients differed significantly between both potato varieties and applied cooking methods: differences between potato varieties and cooking methods were found for vitamin C, moisture, reducing sugars, fructose, glucose, sucrose, amino acids, essential amino acids, and energy content, whereas significant differences in starch, fibre, fat and protein content were found between cooking methods.     

The effect of frying on anthocyanin stability and antioxidant activity of crisps from red- and purple-fleshed potatoes (Solanum tuberosum L.)

Red- and purple-fleshed potatoes (Solanum tuberosum L.) are a good source of polyphenols, mainly anthocyanins as one of the most important components. The chemical composition with reducing sugars and the total polyphenol contents were analyzed in four purple potato varieties (Salad Blue, Vitelotte, Valfi, Blue Congo) and three red-fleshed potato varieties (Rosalinde, Herbie 26, Highland Burgundy Red). The anthocyanin composition of raw potato and potato crisps was characterized by high-performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) method. Moreover, the antioxidant activity was measured with the radical scavenging assays using 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as ferric reducing ability of plasma assay (FRAP). In addition, colour parameters in prepared potato crisps were evaluated. Both red and purple-fleshed potato varieties contained high levels of total polyphenols (227–845 mg 100 g⁻¹ dry weight) and anthocyanins (21–109 mg 100 g⁻¹ dry weight). The process of frying caused degradation of anthocyanin compounds (38–70%). The HPLC–MS/MS analysis showed that pelargonidin and malvidin derivates were more stable during frying than petunidin derivatives. Although frying process affected the anthocyanin and polyphenol levels, obtained potato crisps exhibited bright intensive colour and good antioxidant activity.     

Evaluation of the Maillard reaction in potato crisps by acrylamide, antioxidant capacity and color

This study aimed at examining potential risks and benefits associated with the frying process for potato crisps. The effects of reducing sugars, frying temperature and time on acrylamide and total antioxidant capacity (TAC) of potato crisps were studied. TAC of potato crisps ranged between 13 and 68 mmol Trolox Eq./kg, depending on the sugar concentration and frying conditions. Acrylamide and TAC variables correlated very well for potato crisps (r = 0.8322). There was also close linear correlation between CIE (Commission Internationale de l’Eclairage) a* and TAC values of potato crisps fried at different time–temperature conditions with different initial sugar concentrations. Similar to the CIE a*, the total color difference (ΔE) also showed a high correlation with acrylamide (r = 0.7870) and TAC (r = 0.7678). Acrylamide and TAC of potato crisps appeared less sensitive to a variation in lightness (L*) having correlation coefficients of 0.7302 and 0.7630, respectively. On the other hand, CIE b* values had lack of correlation with acrylamide (r = 0.2612) and TAC (r = 0.3503) of potato crisps.     

Effect of storage conditions on methanol content of fruit and vegetable juices

Methanol contents of fresh squeezed juices from 10 fruits and 5 vegetables were determined and the relation of methanol release from stored juices on the physico-chemical properties including degree of esterification (DE), total pectin content, pH value, titratable acidity and the hydrolytic activities of pectinesterase (PE), polygalacturonase (PG), cellulase (CE) and pectate lyase (PAL) of fresh squeezed juices were investigated. The range of methanol content in fresh squeezed juices of fruits and vegetables were 1.14–6.77 and 2.04–10.92 mg/100 mL, respectively, but increased to 1.13–14.82 and 4.73–24.08 mg/100 mL after 3 h storage. In most of the juices, the increase of methanol content was significant (p<0.05) after 3 h storage, except grape (4 and 30 °C), guava (4 °C), lemon (4 and 30 °C), and star fruit (4 °C). The methanol levels above 10 mg/100 mL (the given limit of alcoholic beverages) were found in fresh tomato juices (squeezed and stored) and several other stored juices including pea shoot juices (after 60 min storage), star fruit juices (after 180 min storage), papaya juices (after 180 min storage), pineapple juices (after 180 min storage) and Valencia orange (after 30 min storage), and alfalfa sprout juices (after 60 and 120 min storages for 4 and 30 °C, respectively). After analyzing with multiple regressions, methanol release was positively associated with enzyme activities of PE and PAL, while negatively associated with total pectin content in fruit juices. In vegetable juices, methanol release was positively associated with PE activity, pH value and titratable acidity, while negatively associated with PG activity.     

Acrylamide levels in cooked rice,tomato sauces and some fast food on the Italian market

This study reports the results of evaluation of acrylamide levels in some foods that are common on the Italian market. Three foods commonly found in the national diet (rice, tomato sauce and fast food), were examined with the gas chromatograph (GC)/mass spectrometer (MS) analytical method. Results show that rice differs from risotto with respect to acrylamide levels: values of less than 50 μg/kg, for boiled rice, increase to 113 μg/kg when various ingredients are added to produce risotto. Similar results were found for tomato sauce on the Italian market: acrylamide values were less than 50 μg/kg for simple tomato sauce, to 124 μg/kg when other ingredients such as olives and capers were added. Fast foods (e.g., fried potatoes) contained the highest observed acrylamide levels, probably from cooking methods and acrylamide-rich precursors. For two fried potatoes of the same type, very differentiated values resulted (136 and 294 μg/kg).     

Preparation and heat resistance study of porcine reproductive and respiratory syndrome virus sugar glass vaccine

To improve the preservation period without cold-chain of the live attenuated vaccine of porcine reproductive and respiratory syndrome (PRRS), a set of thermostable formulations composed of trehalose, tryptone and other protectants were dried by vacuum foam drying (VFD) along with PRRSV solutions. In the 37 °C and 45 °C resistance ageing test, the dried foam vaccine showed significant thermostability, and the virus titer lost 0.8 Log₁₀ at 37 °C for 4 months, 1.0 Log₁₀ at 45 °C for 25 days. Furthermore, the foam vaccine could be stored at 25 °C for at least one year. Besides, the vaccine preserved in 37 °C, 25 °C and 4 °C for 3 months were inoculated on 20-days old piglet, and the serum titer was monitoring by ELISA kit. Inoculated two weeks later, the ELISA titer were all qualified and had the similar level compared to the commercial vaccines of the lyophilization dosage.     

Stability of heat stable,live attenuated Rotavirus vaccine (ROTASIIL®)

Vaccines currently available across the globe are stored and transported in a continuous cold-chain at 2–8 °C or below −20 °C. A temperature excursion outside this range affects the potency of the vaccines. Such vaccines need to be discarded leading wastage. The Rotavirus disease burden is predominantly reported in developing and low-income countries and therefore, has entered or poised to enter their national immunization programs. These countries already have several limitations for effective storage, maintenance and distribution of vaccines in a cold-chain and this introduction is expected to further stress this fragile ecosystem. To help mitigate the cold chain related issues, SIIPL has developed a thermostable rotavirus vaccine ROTASIIL® which can be stored at a temperature below 25 °C for 36 months, completely by-passing the standard 2–8 °C cold storages. In addition it has the capability to withstand temperatures of 37 °C and 40 °C for 18 months and short term exposure to 55 °C. It can also tolerate a temperature shock of being thawed from an extreme cold temperature of −20 °C to a high temperature of 42 °C. The vaccine contains serotypes G1, G2, G3, G4 and G9 (UK-Bovine reassortant strains procured from National Institute of Health-USA). The vaccine is recently licensed in India.     

Vitamins profile as an indicator of the quality of frozen Agaricus bisporus mushrooms

Fresh mushrooms have been known as a functional food, especially as a good source of vitamins from B-group. The work determined the effect of pre-treatment (blanching, vacuum soaking), method of freezing (air-blast and cryogenic), temperature (−20 °C, −30 °C) and period (0, 6, 12 months) of frozen storage on the vitamins profile in white A. bisporus. Niacin and riboflavin were the most abundant vitamins in all mushroom products (154–362 mg; 1.57–5.06 mg/100 g dm, respectively). The greatest influence on the vitamins profile was pre-treatment. The highest levels of vitamin B₃ and L-ascorbic acid were found in blanched mushrooms, vitamin B₆ in vacuum soaked, α-tocopherol and vitamin B₁ in unblanched. The greatest losses occurred between the 6th and 12th month of storage, and therefore mushrooms should not be stored for longer than 6 months. After storage the greatest losses were found in vitamin B₁, L-ascorbic acid and α-tocopherol. A. bisporus mushrooms contain small amounts of L-ascorbic acid and α-tocopherol, therefore the level of vitamin B₁ may be regarded as a quality indicator. The freezing method affected only vitamin B₃, with levels higher after cryogenic than air-blast freezing. The storage temperature generally had no effect on vitamin levels.     

Method performance study for total solids and total fat in coconut milk and products

Many analytical methods are available for total solids and total fat in various kinds of food. However, none is specific for coconut milk and products. The aim of this study was to establish methods and to conduct the method performance study on determination of total solids and total fat in coconut milk and products. In the single laboratory study, three methods for total solids determination were conducted: drying in hot air oven at 102 ± 2 °C and at 130 ± 3 °C and drying in vacuum oven at 70 °C, 70 mmHg, as well as three methods for total fat determination: direct extraction method, acid hydrolysis method and alkaline hydrolysis method. Sixteen samples of aqueous coconut milk and coconut milk powder were selected as test materials. Total solids and total fat contents were analyzed in 10 individual samples of each test material (N = 10). The statistical analysis (one-way ANOVA) showed no significant difference for total solids and no difference for total fat content by the used methods (p > 0.05). Since the drying method by hot air oven at 102 ± 2 °C is the most commonly used for total solids in food laboratories, it was selected for further inter-laboratory study. For total fat determination, the alkaline hydrolysis method (Roese–Gottlieb) was selected for further inter-laboratory study since it is less time-consuming and involves fewer steps than the acid hydrolysis method. Seventeen laboratories participated in the inter-laboratory study and seven representative test materials with varying levels of total solids and fat were used. The method performance characteristics are presented. These methods were proposed to CODEX and endorsed as the CODEX standard methods (type I) for aqueous coconut milk and coconut cream analyses.     

Rabies vaccine preserved by vaporization is thermostable and immunogenic

A rabies vaccine that is thermostable over a range of ambient environmental temperatures would be highly advantageous, especially for tropical regions with challenging cold-chain storage where canine rabies remains enzootic resulting in preventable human mortality. Live attenuated rabies virus (RABV) strain ERAG333 (R333E) was preserved by vaporization (PBV) in a dry, stable foam. RABV stabilized using this process remains viable for at least 23 months at 22 °C, 15 months at 37 °C, and 3 h at 80 °C. An antigen capture assay revealed RABV PBV inactivated by irradiation contained similar levels of antigen as a commercial vaccine. Viability and antigen capture testing confirmed that the PBV process stabilized RABV with no significant loss in titer or antigen content. Live attenuated and inactivated RABV PBV both effectively induced RABV neutralizing antibodies and protected mice from peripheral RABV challenge. These results demonstrate that PBV is an efficient method for RABV stabilization.     

Oxalate content of cormels of Japanese taro (Colocasia esculenta (L.) Schott) and the effect of cooking

Taro (Colocasia esculenta L. Schott) is a major starchy food crop in parts of Asia and the Pacific Islands and is grown as a minor crop in New Zealand. Soluble, insoluble and total oxalate content of the cormels of Japanese taro cultivars, Akame, Ishikawa-wase, Yamato-wase and an unnamed cultivar were determined by HPLC following hot water (80 °C) or hot acid (0.2 mol/L HCL) extractions. Oxalate analysis was carried out on the peeled raw, boiled (40 min) and baked corms (180 °C for 40 min). Akame contained the highest level of total oxalate (171.4±11.4 mg/100 g fresh weight (FW)) in the raw tissue and was significantly higher than the other three cultivars (P<0.001). The raw tissue of the four cultivars contained a mean of 60.6% soluble oxalates; boiling reduced the level of soluble oxalate in the cooked tissue to below detectable levels as soluble oxalates leached into the cooking water. Baking led to a significant reduction in the moisture content of the taro concentrating oxalates in the cooked tissue (overall mean, 229.0±34.4 mg/100 g FW). The results from this study suggest that baked taro corms contain moderate amounts of oxalates.     

Composition of oxalates in baked taro (Colocasia esculenta var. Schott) leaves cooked alone or with additions of cows milk or coconut milk

Taro (Colocasia esculenta var. Schott) is a major staple food crop in parts of Asia and the Pacific Islands and two different cultivars of taro plants Taro Tonga (C. esculenta) and Taro Futuna (Xanthosoma sagittifolium), known respectively as Maori and Japanese, are grown as a minor crop in New Zealand. The leaves are either boiled or baked before they are consumed. In this experiment the leaves were baked at 150 °C for 1.5 h either alone or with additions of cows milk and coconut milk prior to baking. Oxalate contents of both cultivars of leaves were determined following extraction by either hot distilled water (80 °C) to give soluble oxalates or hot (80 °C) acid (0.2 mol/l HCl) to give total oxalates. The extracted oxalates were then determined by HPLC chromatography. Baked Maori-type taro leaves contained 719.3 ± 12.0 mg total oxalates/100 g fresh weight (FW) and 365.9 ± 11.4 soluble oxalates/100 g FW while baked Japanese-type leaves contained 533.9 ± 14.9 mg total oxalates/100 g FW and 352.6 ± 8.4 mg soluble oxalates/100 g FW. The total and soluble oxalate content of the baked leaves was considerably reduced when the leaves were baked with cows milk, coconut milk or mixtures of these two (mean % reduction of total oxalates was 43.2 ± 3.8% while the mean % reduction of soluble oxalates was 58.7 ± 1.8%).     

Protective immunity against Megalocytivirus infection in rock bream (Oplegnathus fasciatus) following CpG ODN administration

Rock bream iridovirus (RBIV) disease in rock bream (Oplegnathus fasciatus) remains an unsolved problem in Korea aquaculture farms. CpG ODNs are known as immunostimulant, can improve the innate immune system of fish providing resistance to diseases. In this study, we evaluated the potential of CpG ODNs to induce anti-viral status protecting rock bream from different RBIV infection conditions. We found that, when administered into rock bream, CpG ODN 1668 induces better antiviral immune responses compared to other 5 CpG ODNs (2216, 1826, 2133, 2395 and 1720). All CpG ODN 1668 administered fish (1/5 µg) at 2 days before infection (1.1 × 10⁷) held at 26 °C died even though mortality was delayed from 8 days (1 µg) and 4 days (5 µg). Similarly, CpG ODN 1668 administered (5 µg) at 2 days before infection (1.2 × 10⁶) held at 23/20 °C had 100% mortality; the mortality was delayed from 9 days (23 °C) and 11 days (20 °C). Moreover, when CpG ODN 1668 administered (1/5/10 µg) at 2/4/7 days before infection or virus concentration was decreased to 1.1 × 10⁴ and held at 20 °C had mortality rates of 20/60/30% (2 days), 30/40/60% (4 days) and 60/60/20% (7 days), respectively, for the respective administration dose, through 100 dpi. To investigate the development of a protective immune response, survivors were re-infected with RBIV (1.1 × 10⁷) at 100 and 400 dpi, respectively. While 100% of the previously unexposed fish died, 100% of the previously infected fish survived. The high survival rate of fish following re-challenge with RBIV indicates that protective immunity was established in the surviving rock bream. Our results showed the possibility of developing preventive measures against RBIV using CpG ODN 1668 by reducing RBIV replication speed (i.e. water temperature of 20 °C and infection dose of 1.1 × 10⁴).     

Evaluation of extraction parameters for total oxalate determination in spinach using Design of Experiment analysis

The interaction of pH, temperature and time on the acid extraction of total oxalates from homogenised fresh stems and leaves of spinach (Spinacia oleracea L.) were investigated. The extractions were carried out using HCl solutions between pH 0.93 and 5.81 and temperatures ranging from 25 to 95 °C. The extraction times ranged from 15 to 120 min. The released oxalate was measured using a standard HPLC method. A Design of Experiments (DOE) method using Design Expert DX9 was used to determine the optimum extraction parameters. Increasing the extraction time from 15 to 120 min had no significant effect while increasing the extraction temperature from 25 to 95 °C significantly (P < 0.01) increased the recovery of total oxalates. Reducing the pH of the extraction solutions from 5.81 to 0.93 significantly (P < 0.001) increased the total amount of oxalate extracted. There was no significant correlation between the pH of the extraction solutions and the extraction temperatures. The highest amount of extracted oxalate content in this experiment (856.57 mg/100 g FW) was obtained using an HCl solution of pH 0.93 (0.1 M HCl) at 95 °C.     

Effects of soaking conditions on the antioxidant potentials of oolong tea

The antioxidant properties of water extracts of oolong tea (Commercial name: Fenghuangdancong) prepared using different soaking temperatures and times were investigated. The yield of powdered extract ranged from 6.7% at 80 °C for 3 min soaking to 22.7% at 100 °C for 10-min soaking. Oolong tea extracts reduced peroxidation of peanut oil and delayed the time of POV20 (peroxide value). Among these soaking treatments, soaking for 10 min in 100 °C water produced extracts with the greatest ability to inhibit the peroxidation of peanut oil. As well, the SC50 (scavenging-percentage) of the α, α-diphenyl-β-picrylhydrazyl radical (DPPH radical) was 0.119 mL of oolong tea extract using 3-min soaking at 100 °C, which is closed to the SC50 of 0.109 mL (2 mg/mL) for vitamin C. The DPPH radical scavenging activity of oolong tea extracts increased with increasing temperature of the soaking water indicating greater extraction of antioxidant compounds. In addition, inhibition of oxidation of peanut oil and DPPH radical scavenging activity by water extract of oolong tea was associated with polyphenol concentrations. Sensory assessment, found that the water extract of oolong tea using 3-min soaking at 95 °C had the strongest aroma and sweetness attributes.     

Glutathione is a highly efficient thermostabilizer of poliovirus Sabin strains

Glutathione (GSH) is the most abundant thiol peptide in animal cells and has a critical role in antioxidation. GSH was reported to be essential for stabilization of some enteroviruses, including poliovirus (PV), during viral morphogenesis. Here, we explored the potential use of GSH as a thermostabilizer of oral poliomyelitis vaccine (OPV) formulations. GSH significantly protected the three types of PV from heat-inactivation in a concentration-dependent manner. At a GSH concentration of 20 mM, nearly complete protection was observed against heating temperatures up to 53 °C for 2 min. GSH also markedly protected PV1 from heat-inactivation and this up to 6 h at temperatures of 44 °C and 46 °C and 3 h at 48 °C. The fact that GSH is naturally present at high concentration in the human body makes it an efficient candidate stabilizer for OPV formulations.     

A thermostable presentation of the live,attenuated peste des petits ruminants vaccine in use in Africa and Asia

The research objective was to develop a thermostable vaccine against peste des petits ruminants (PPR), a morbilliviral disease of small ruminants targeted for eradication that is a major constraint on the livelihoods of the rural poor throughout much of Africa and Asia. Although existing PPR vaccines provide life-long immunity, they require continuous refrigeration. This limits their utility in developing countries. Methods for the lyophilization of a related morbillivirus, rinderpest (RP), resulted in vaccine that could be used in the field for up to 30 days without refrigeration which was a major contribution to the global eradication of RP completed in 2011. The present research applied the rinderpest lyophilization method to the attenuated Nigeria 75/1 PPR vaccine strain, and measured thermostability in accelerated stability tests (AST) at 37 °C. The shelf-life of the vaccine was determined as the time a vial retained the minimum dose required as a 25-dose presentation at the specified temperature. A lactalbumin hydrolysate and sucrose (LS) stabilizer was compared to stabilizers based on trehalose. PPR vaccine produced using the Xerovac drying method was compared to vaccine produced using the rinderpest lyophilization method in AST. LS vaccine was evaluated in AST at 37, 45 and 56 °C and an Arrhenius plot was constructed for estimation of stability at temperatures not tested. Vaccines produced using LS and the rinderpest method of lyophilization were the most stable. The shelf-life of the Xerovac preparation was 22.2 days at 37 °C. The three LS vaccine batches had shelf-lives at 37 °C of 177.6, 105.0 and 148.9 days, respectively, at 37 °C. At 56 °C, the shelf-life was 13.7 days. The projected half-life at 25 °C was 1.3 years. This is sufficient thermostability for use without a cold chain for up to 30 days which will greatly facilitate the delivery of vaccination in the global eradication of PPR.     

Acridine derivatives (PANHs,azaarenes) in raw,fried or grilled pork from different origins,and PANH formation during pork thermal processing

The aim of this work was to determine level of azaarenes (PANHs) in raw pork and to investigate their formation during meat frying or grilling, in particular to verify a suggestion that endogenous vitamin E might inhibit production of azaarenes. Azaarene concentration in raw pork samples from various origins ranged from 2.75 ng g⁻¹ to 3.69 ng g⁻¹ (2.75–2.93 ng g⁻¹ in meat of Polish Landrace pigs, 3.00–3.69 ng g^–1 in meat of hybrid Duroc × Polish Landrance pigs). PANH formation during frying of pork meat was not confirmed. On the other hand, PANHs were indeed formed during grilling; their levels ranged from 6.21 ng g⁻¹ to 8.08 ng g^–1. No inhibition influence of vitamin E on formation of PANHs on was found either in fried or grilled pork meat.     

Stability of vitamin C in fruit and vegetable homogenates stored at different temperatures

Vitamin C loss was compared in homogenized raw broccoli, potatoes, spinach, strawberries, oranges, and tomatoes; baked potatoes; steamed broccoli and spinach; and pasteurized orange juice after storage under residual nitrogen under refrigeration, and frozen at conventional (−10 to −20 °C) and ultra-low (<−55 °C) temperatures for 1, 3, and 7 days. Additional foods (cantaloupe, green sweet peppers, collard greens, clementines) were monitored for 3–4 years at <−55 °C. Total ascorbic acid was quantified using high-performance liquid chromatography and detailed quality control measures. No decrease occurred in any of the foods after 7 days at <−55 °C. Under refrigeration the largest decreases were in raw spinach and broccoli, averaging (mg/100 g) 9.5 (29%) and 33.1 (29%), respectively, after 1 day and 31.0 and 77.0 after 7 days (94% and 68%, respectively). With conventional freezing, vitamin C was stable for 7 days in most of the products studied; minor losses occurred in raw spinach and broccoli after 1 day but were substantial after 3 days, 6.9 mg/100 g (23%) and 17.0 mg/100 g (15%), respectively; and 7 days (13.1 and 32.0 mg/100 g). For homogenates stored long-term at <−55 °C, vitamin C loss occurred in only cantaloupe, collard greens, and one sample of raw potatoes, all before 50 weeks.     

Variations in the carotenoid and anthocyanin contents of Korean cultural varieties and home-processed sweet potatoes

The sweet potato is an important industrial crop and a source of food that contains useful dietary fiber and vitamins. Recently, orange- and purple-fleshed varieties have come under the spotlight due to their healthful components, carotenoids and anthocyanins, respectively. In this study, an HPLC-DAD method was applied to determine the carotenoid composition and content in nine Korean cultural varieties of sweet potato. Changes in carotenoid contents and composition were also observed during home-processing of an orange-fleshed cultivar with high carotenoid content (530 ± 60 μg/g of dry weight, DW as all-trans-β-carotene). A loss of the carotenoids was observed for all of the home-processing methods examined; the baked or boiled or steamed sweet potatoes had higher amounts of all-trans-β-carotene (246 ± 34, 253 ± 29 and 240 ± 21 μg/g DW, respectively) than pressure-cooked, sautéed and fried ones (194 ± 21, 201 ± 28 and 111 ± 19 μg/g DW, respectively). Interestingly, cis-isomer of the all-trans-β-carotene, 13Z-β-carotene was found in elevated amounts in all of the processed samples, particularly in baked, pressure-cooked and steamed sweet potatoes compared to control. Variations in anthocyanin content in the nine cultural varieties and home-processed sweet potatoes were also determined by an HPLC-DAD method.