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Plant pigments such as anthocyanins and carotenoids have been shown to be beneficial to human health. Therefore, carrot lines of different colors have been recently developed. This study aimed to characterize terpenoid, carotene, anthocyanin, and soluble solids content and antioxidant activity levels in orange, yellow, black, and purple carrots to develop new color carrot cultivars with more nutrients, health benefits, and consumer acceptance. Both individual and total terpenoid content greatly varied among breeding lines. Each line had a unique composition, and there was no general pattern between color and terpenoid content. Orange carrot roots had high levels of α-carotene, β-carotene, and total carotenoids compared with yellow. Red carrots were characterized by high lycopene content, and black carrots exhibited identical levels of lycopene content to yellow carrots. Leaf tissues contained lutein as the main carotenoid followed by β-carotene. There was no clear relationship between leaf and root carotene profiles and content. Black and purple root colors were determined by composition and amount of anthocyanin compounds, and about five major compounds were detected in this study. Total anthocyanin content was high in solid black carrots and decreased as the interior root color contained more yellow, with low and trace levels in purple and orange carrots, respectively. Soluble solid content ranged between 4.0 and 9.5 °Brix among lines. Anthocyanin content was highly correlated with antioxidant activity. Each color of carrot contained different levels of the tested compounds and may require extensive breeding to obtain desired levels.

The growth of a flower stem (bolting) causes a decrease in yield and marketability in onion. We have examined the effects of bolting and of the removal of flower stems at different lengths on the growth and chemical qualities of onion bulbs. Two onion cultivars, ‘Mapshihwang’ (M) and ‘Yeongmihwang’ (Y), were grown in the field and allowed to bolt. The treatments included the removal of three different lengths of the flower stem (short, medium, or long), uncut flower stem until harvest, or unbolted plants (control). Bolting and the length of the flower stem removed had no effect on bulb diameter but caused a decrease in bulb weight. The flower stems were generated after three to five scales; bolting and flower stem removal reduced the number of scales by approximately one scale. The total soluble solid content (SSC) and the total sugar content were also unaffected by bolting and the length of the flower stem removed. The pungency of the M and Y cultivars, being an average of about 5.0 and 2.8 μmol·mL-1 pyruvic acid, respectively, was not changed. The total quercetin content showed various responses to the treatments and no clear differences compared to the unbolted bulbs. The total phenolic content was not changed by bolting or the stem removal treatments. In conclusion, bolting and removal of the flower stem caused a decrease in bulb weight, whereas the SSC, total sugar content, pungency, quercetin content, and total phenolic content remained unaffected, indicating that the chemical qualities of the bolted bulbs was identical to those of the unbolted, normal bulbs. The removal time of the flower stem had no significant difference on bulb quality.

Sweet or low-pungency onions have become popular in fresh market onion production and are commonly produced using low sulfur soil and/or innate low-pungency cultivars in specific regions. However, there have been very limited breeding efforts to create true low-pungency cultivars. This study reports the process and progress of a recurrent selective breeding program to produce low-pungency lines in short-day type onions. Two parent populations, 'T81079' (n = 754) and 'T81082' (n = 347), with mean pungencies of 4.1 and 3.5 mM pyruvic acid, respectively, were tested for pungency and bulbs were divided into five groups according to their pungency levels. Twenty bulbs were selected from each group and grown for seeds by mass-pollination. The pungency in bulbs produced from the seeds of each group showed genetic shifts towards the selection differential. The realized heritability (h2) values in the two populations varied between 0.48 and 2.21 or –2.09 and 6.16, respectively, and showed no consistency or reliability. However, a regression analysis between the selection differentials and the response to selection showed coefficients of 0.65 and 0.54 with high significance (r2 = 0.94**. After three recurrent selections of 20 bulbs from the lowest pungency progenies, we obtained two populations with mean pungencies of 2.6 n = 1209 and 2.5 n = 1781 mM pyruvic acid, showing a reduction in pungency by 1.0–1.5 mM, as compared to the initial parent populations. The 4th selection of 20 bulbs from one of these populations yielded 11 families of onions with a mean pungency of 1.5 mM pyruvic acid. Our study demonstrated that the recurrent selection of low pungency actually shifted the pungency distribution toward lower pungency levels, and therefore developing low-pungency (1.5 mM pyruvic acid) lines will be feasible in about 10 years in short-day onions.

We have investigated the antioxidant activity (AOA) of 15 short-day onions with white, yellow, or red colors and elucidated the relationships between pungency, anthocyanins, quercetin, and the AOA levels. There were substantial variations in both the pungency and total soluble solid content, which showed varying responses by bulb colors. The AOA in white or red onions tended to have low and high levels, respectively. However, there were many exceptions. The AOA levels assessed by the Folin–Ciocalteu (F–C) assay ranged between 440 and 785 μg/mL. The AOA levels based on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were between 19.1 and 79.8 μg/mL and displayed 10- to 20-fold differences. There was no correlation between the pungency and the AOA levels. The F–C assay showed no or low correlation with anthocyanin (r2 = 0.07) and quercetin (r2 = 0.59) contents, respectively. The DPPH assay showed correlations with anthocyanin (r2 = 0.65) and quercetin (r2 = 0.76) contents. Therefore, the onions with higher levels of anthocyanin and quercetin would have still higher AOA levels. Samples with alliinase action showed higher AOA levels than the samples without enzyme action. Onion juice without anthocyanin and flavonoids still contained considerable AOA levels. The methanol extract and fresh onion juices showed similar AOA levels by the F–C assay.

BACKGROUND Onion pungency is estimated by measuring the pyruvic acid content in juice extracted from fresh tissues. We compared pyruvic acid content and its variation in the juices extracted by the pressing, maceration, blending with no water, or blending with water (blend/water) methods. RESULTS There were considerable differences in the pyruvic acid content and coefficient of variation (CV) among these methods, and there was an interaction between the onion cultivars and the juice extraction methods. The pressing method showed over 30% CV in the quartered or composite samples. The blend/water method showed the greatest pyruvic acid content in the shortday-type (‘TG1015Y’ and ‘Texas Early White’) onions, while the pressing method showed the greatest pyruvic acid content in the longday-type onions. The blend/water method, which gave ratios between 1:1 and 1:4 (w/w), showed the same pyruvic acid content. The blending (no water) method had the highest correlation, followed by the maceration method. The lowest correlations were found with the pressing method and the blend/water method. CONCLUSIONS Complete homogenisation of tissues with 1:1 or greater ratios of water was necessary for the maximum consistency and full development of the pyruvic acid reaction for onion pungency measurement. © 2015 Society of Chemical Industry

Ultraviolet (UV)-A, -B, and -C were radiated to full-ripe blueberries (cv. 'Duke'), and their effects on fruit qualities and phytonutrients during subsequent cold storage were investigated. The blueberries were exposed to each UV light at 6 kJ/m(2) and then stored at 0 °C for 28 days. Weight loss and decay of the fruits after UV treatment were significantly decreased during the cold storage. The total phenolics and antioxidant activities of blueberries after UV-B and -C treatments were always higher than those of the control and UV-A treatment. Individual anthocyanins were markedly increased during the 3 h after the UV-B and -C treatments. The correlation matrix between total phenolics, anthocyanins, and antioxidant activity measured by the 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) assay indicated a significantly close correlation with the individual anthocyanin contents. It was confirmed that the prestorage treatments of UV-B and -C increased the storability and phytochemical accumulation of the full-ripe 'Duke' blueberries during cold storage.

Humic substances are produced from decomposing plant materials and have various physico-chemical properties that improve soil environments, making them beneficial to the growth and quality of plants. In this study, we examined the effects of fulvic acid and humic acid by foliar or soil application on the yield and quality of potato tubers. Fulvic acid was sprayed onto the leaves of potato plants (cv. Atlantic, Korean name Daeseo) at 50, 60, and 70 days after planting with 1000-X, 750-X or 500-X diluted stock solution. Additionally, humic acid was incorporated into soil at a rate of 40 or 80 g∙m−2 with 8 kg of soil-mix before planting potato seeds. There was no significant difference in the number of tubers, total yield, or chemical composition of tubers treated with fulvic acid, but the weight of extra-large tubers increased, which resulted in a substantial increase of the incidence of hollow heart. Soil application of humic acid had no effect on tuber size, total yield, or other chemical compositions of tubers. However, the 80 g∙m−2 humic acid treatment resulted in increased mineral contents in the soil and tubers and substantially decreased incidence of hollow heart. Humic acid was believed to be beneficial to increasing P and K contents in both soil and tubers. These findings indicate that fulvic acid and humic acid have no clear promotional effects on tuber growth, but may lead to a high incidence of hollow heart.

Summary Measuring the total phenolic content in wine is important in estimating the taste and health benefits of wine. We developed an automatic Folin–Ciocalteu (F-C) method to reduce processing times (3 min), human errors and waste volume as compared it to the manual method. The gallic acid standard responded linearly up to 5000 μg mL−1, and the wine dilution series responded linearly between four- and sixteenfold dilutions. Anthocyanins showed slower reaction rate compared with wine, gallic acid and quercetin, while ascorbic acid showed the fastest rate. Fructose and glucose at the 10% level showed approximately 8% interference in port wines, and the interference was thought to be negligible in most dry wines containing

Short-day onions (Allium cepa L.) grown in the southern regions of the United States are commonly undercut and then dried for a few days before the bulbs are clipped and harvested. We conducted a study to evaluate the effects of leaf cutting on bulb weight and pungency of short-day onions after plant lifting in ‘TG 1015Y’, ‘Legend’, and ‘Texas Early White’ cultivars. When about 50% of the leaf had collapsed, plants were lifted from the field and the leaf was either cut at the neck (cut) or left intact (uncut, control). The plants were laid out to dry for 0, 3, or 7 days in a greenhouse with natural ventilation and the pungency and weights of the bulbs and leaves (partially dried to approximate normal field curing or dry weight) were measured. In a bulb–leaf paired test, bulb pungency was retained at the initial level in the cut treatment, while it showed an increasing trend in the uncut treatment, resulting in a gain of ˜0.8 μmoles mL−1 after 7 days in ‘TG 1015Y’. However, leaf pungency in the uncut treatment had 2.5 and 4.8 μmoles mL−1 less than that of the cut treatment after 3 and 7 days, respectively. Among cultivars, bulb pungency generally showed that the cut treatment had lower pungency levels, with some variation in change patterns and magnitudes of difference by the cultivar. The mildest cultivar ‘Legend’ had no difference but the most pungent cultivar ‘TEW’ showed 1.0–1.3 μmoles mL−1 less pungency by the cut treatment. Bulb weight was not reduced by the cut treatment, while leaf dry weight was generally heavier in the three cultivars. We considered that the lower bulb pungency in onions from cut plants was attributed to the severance of translocation of flavor compounds from leaf to bulb. Therefore, leaf clipping at the time of lifting and subsequent field curing is beneficial for producing less pungent onions for some cultivars.

Bioactive compounds in plant-derived foods provide essential human health benefits. However, the content and types of bioactive compounds may vary based on genetic and environmental factors. The present study examined the impacts of cultivar, fruit maturity stage (mature versus immature), and growing season (2008, 2009) on the concentration of bioactive compounds in diverse pungent and non-pungent peppers. Significant interactions were observed among cultivars, maturity stages, and growing seasons. Mature peppers generally had the highest content of ascorbic acid (782.0–2305.3 μg/g FW in 2008 and 693.5–2817.2 μg/g FW in 2009), and capsaicinoids (115.5–338.9 μg/g FW in 2008 and 93.8–326.3 μg/g FW in 2009) compared to immature peppers. Paprika-type peppers generally had the highest contents of ascorbic acid and flavonoids especially in mature fruits, while capsaicinoids were higher in all mature stage peppers. Flavonoid concentrations varied considerably depending on cultivar and maturity stage. Total phenolics were also significantly higher in mature fruits compared to immature peppers in both years. A positive correlation between total phenolics and DPPH radical scavenging activity was observed. This indicates that the health beneficial components in peppers could also vary as a function of cultivar, fruit developmental stage and production season. The genetic variability in bioactive compounds found in this study constitutes a useful genetic base for improving the nutrient quality of peppers.

The composition of betalain, red or yellow pigments, and betaine (trimethylglycine or glycinebetaine) of nine beetroot ( Beta vulgaris L.) cultivars produced in the greenhouse or field was studied. Inhibition of HepG2 cell proliferation by betanin and betaine was also tested. Four predominant betalains, two betacyanins (betanin and isobetanin) and two betaxanthins (vulgaxanthin I and miraxanthin V), were isolated and quantified. Betanin and vulgaxanthin I were the major compounds in red and yellow beetroot extracts, respectively, and they comprised90% of the betalain content in the tested cultivars. The total betalain content of beetroots produced from the field was between 650 and 800 μg/g fresh weight, approximately 25% higher than those from the greenhouse. The betaine content of the beetroot grown in the field was between 3.0 and 4.8 mg/g fresh weight, approximately 20% higher than in plants from the greenhouse. There was great variation among the cultivars with respect to their contents of betalains and betaine. In vitro cancer cell cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay on HepG2 cells after exposure to betanin and betaine at concentrations ranging from 0 to 400 μg/mL and from 0 to 800 μg/mL for 48 h, respectively. Betanin resulted in a 49% inhibition of HepG2 cell proliferation at 200 μg/mL, and betaine yielded a 25% inhibition at 800 μg/mL, implying a higher cytotoxicity of betanin compared with betaine. The results indicated that the contents of health-beneficial compounds in beetroots, betalains and betaine, could be increased by modifying the growing conditions and that betanin and betaine extracted from beetroots had some anticancer effects against HepG2 cells.

Onion is an excellent source of quercetin (Q), which is known to have various health benefits. In this study, we investigated the distribution of quercetin glucoside (QG) compounds among dry skins, semi-dry skins, and fresh onion scales; changes in the concentrations of QG compounds in onion bulbs stored at various temperatures for five months; and changes in QG concentrations in the etiolated leaves irradiated by ultraviolet (UV) or visible light. Among scales of a bulb, total quercetin (TQ) concentrations were greatest in the outer-most scales (dry skins) and were gradually reduced toward the inner fresh scales on a fresh weight basis. However, on an area basis, TQ content peaked in the first fresh scale and was lower in the dry skins or the inner fresh scales. The QG content in the bulbs stored in a controlled atmosphere (CA) did not change significantly, while the concentrations in bulbs stored at 30 °C increased by about 50% and then returned to the initial levels. We observed increases of quercetin-3,4′-diglucosde (Q3,4′G), accompanied by a reduction of quercetin-4′-glucoside (Q4′G), at 30 and 24 °C storage, suggesting a relationship between QG concentration and storage temperature or metabolic changes. However, it was not clear if there was a net synthesis of the TQ compounds at the 30 and 24 °C storage. In the sprouting leaves under the different lights, Q4′G and Q3,4′G concentrations increased the most when exposed to UV light and, to a lesser extent, when exposed to visible light; however, even the samples in the dark condition showed a slight increase in QG compounds. We did not observe the synthesis of QG in the white onion leaves. Our results confirm that the synthesis of QG compounds is enhanced by UV light and, to a lesser extent, by visible light.

Genetic diversity is present in the Capsicum genus for fruit size, shape, color, length, firmness, flavor, and even concentrations of different phytochemicals. Our goal in this study was to gain a better understanding of the relative ease of incorporating these characteristics into an improved cultivar evaluating a combination of 29 F1 paprika and serrano pepper (Capsicum annuum) hybrids along with 19 of their respective parents. Genotypes were grown and evaluated at the Texas AgriLife Research Center in Weslaco in the spring of 2008. Results confirmed our hypotheses that paprika type material have higher ascorbic acid (AA) and flavonoid (quercetin and luteolin) concentrations, while serrano peppers have higher expression of capsaicinoids (capsaicin and dihydrocapsaicin). We were also able to identify how productive certain hybrid combinations were at expressing a significant amount of positive heterosis for particular traits. From our Pearson's correlation analyses, we were able to identify the existence of a significant association between such comparisons as fruit weight with fruit diameter, fruit weight with fruit length, and fruit diameter with fruit length. Interestingly, we were also able to identify the presence of a significant association between such comparisons as ascorbic acid with fruit weight, ascorbic acid with fruit length, ascorbic acid with fruit diameter, total flavonoids with fruit weight, and total flavonoids with fruit length. This information, henceforth, allowed us to acknowledge the amount of variability present between these comparisons. In all, our results were able to reveal how effective certain combinations of parent material are toward production of F1 offspring exhibiting improved fruit traits and elevated phytochemical concentrations. Ideally, these results will serve as benchmarks for breeders interested in development of improved lines for these traits.

A molecular marker associated with male fertility restoration was newly identified in onion in this study using random amplification of polymorphic DNA (RAPD) and bulk segregant analysis. A polymorphic amplicon from RAPD reaction was observed in DNA from fertile plants. The amplicon was designated as the RAPD marker OBC14.1000 and a 980-base pair (bp) nucleotide sequence was obtained. Genome walking was performed to obtain the flanking sequences of the OBC14.1000 marker to develop a co-dominant marker. The acquired sequences were a 2049-bp fragment linked to a male-fertile allele and a 1621-bp fragment linked to a male-sterile allele. Approximately 95% similarity was shown when the nucleotide sequences between fertile and sterile alleles were aligned. Using a polymorphic region containing a restriction site of Ava II in a fertile allele, the RAPD marker OBC14.1000 was successfully converted into a co-dominant CAPS marker and it was designated as ACms.1100. It appeared to be positioned much closer to the restorer-of-fertility locus, Ms , based on genotyping analysis as compared to other currently available markers. No putative homology was found to the newly identified ACms.1100 marker sequences through a Blast database search and the identification of sequences is still unknown.

The effects of flesh color, season, and test cross on carotenoid, sugar, and ascorbic acid contents of 20 watermelon genotypes with red, pink, orange, and yellow flesh were examined. Red- and pink-fleshed watermelons contained lycopene (4.8–47.8 μg·g−1 fresh weight), β-carotene (< 3.7 μg·g−1), and lutein (< 0.9 μg·g−1) as the major carotenoids. The orange and yellow watermelons contained complex mixtures of prolycopene, lycopene, and β-carotene with levels less than 7.4, 1.5, and 8.5 μg·g−1, respectively. There were also minor carotenoids, such as violaxanthin, lutein, neurosporene, and zeacarotene in the range of 0–1.4 μg·g−1. Total sugar contents ranged from 24 to 91 mg·g−1, with sucrose, glucose, and fructose as the major sugars. The sugar profiles were divided into sucrose-, fructose-, and non-dominant groups. Higher percentages of glucose and fructose were negatively correlated with the total sugar content. Fairly-low levels of ascorbic acid, less than 28.2 μg·g−1, were measured, and some genotypes had nearly no ascorbic acid. There were only slight differences in ascorbic acid, sugar, soluble-solid, and total-carotenoid contents among 11 genotypes harvested in June and November. Five sets of test crosses showed various trends of heritability of carotenoids, sugars, and ascorbic acid in F1 hybrids. In general, carotenoids and total sugar content tended to be inherited from the parent with lower carotenoid and sugar contents, respectively. Paralleled chemical analyses will be beneficial for efficient progress in breeding efforts and genetic research.

Ascorbic acid (AA) and dehydroascorbic acid (DHA) are reduced and oxidized forms of vitamin C, which are ubiquitously found in various fruits and vegetables. The present study has evaluated and optimized various factors responsible for AA and DHA stability in grapefruit samples. Furthermore, the optimized method was used to quantify these compounds in different fruits and vegetables. The AA stability in the samples was evaluated by extracting grapefruit juice using 1, 3 and 5 g/100 mL metaphosphoric acid (MPA) and trichloro acetic acid (TCA). The AA levels were stable in grapefruit samples extracted with 1, 3 and 5 g/100 mL MPA, whereas TCA extracts showed degradation in 48 h. Among the three reducing agents studied, tris(2-carboxy ethyl) phosphine hydrochloride (TCEP) has efficiently converted DHA at all concentrations and the samples were stable for 48 h at 2.5 mmol/L TCEP. Lower pH favored complete conversion of DHA by TCEP than dithiothreitol. Among various fruits and vegetables analyzed, the highest levels of AA (260.1 mg/100 g) were observed in guava and DHA (58.6 mg/100 g) in parsley samples. The current optimized method prevents the degradation of AA and DHA from fruit and vegetable samples stored at room temperature for two days.

Habanero peppers have become increasingly popular in the United States for supplying unique flavors and high levels of pungency. As consumption of this product increases, development of improved cultivars with elevated phytochemicals will likely result in additional demand from consumers. This study evaluated fruit size, capsaicinoid, and flavonoid concentrations in six Habanero (Capsicum chinense) genotypes grown at three different Texas locations: College Station, Uvalde, and Weslaco. Five of these Habanero experimental hybrids (H1-red, H2-orange, H3-orange, H5-dark orange, and H6-yellow) were developed at Texas A&M University with genetic improvement in numerous traits of interest, and Kukulkan F1 (Kuk-orange) was included as a commercial control. In general, H1-red had the largest fruits in these locations. Capsaicin and dihydrocapsaicin (DHC) concentrations were highest in Kuk-orange followed closely by H5-dark orange and were lowest in H6-yellow. Fruit at Weslaco was larger and contained more capsaicin and DHC than those produced in Uvalde or College Station. Although flavonoid contents were variable and low in all genotypes and locations, H3-orange showed the most stability for use in future crossing schemes to compete against Kuk-orange for this characteristic. Our results suggest that variation in phytochemicals in fruit tissue of Habanero genotypes can be exploited by selecting in an appropriate environment.

The chemical structures of pink-red pigments responsible for ‘pinking’ in macerated onion were tentatively elucidated using HPLC with a diode array detector and tandem mass spectrometry. All pigments were produced in conditions that approximated the natural process as closely as possible, using mixtures of onion thiosulphinates, the enzyme alliinase, and free amino acids. The isotopic distribution of protonated molecules of pink-red pigments produced from individual amino acids indicated the absence of sulphur, with the exception of pigment produced from cystine. The pigments had a basic polymethine framework containing two pyrrole rings (3,4-dimethyl-1 H -pyrrole and 3,4-dimethyl-2,5-dihydro-1 H -pyrrole) bridged by methines. The side chains attached to the nitrogen of the pyrrole rings were derived from the reacting amino acid. The simplest pink-red pigment, produced from glycine, was identified as 2-(2-(3-(1-(carboxymethyl)-3,4-dimethyl-1 H -pyrrol-2(5H)-ylidene)prop-1-en-1-yl)-3,4-dimethyl-1 H -pyrrol-1-yl)acetic acid. The pigment from alanine was identified as 2-(2-(3-(1-(carboxymethyl)-3,4-dimethyl-1 H -pyrrol-2-yl)allylidene)-3,4-dimethyl-2,5-dihydro-1 H -pyrrol-1-yl)propanoic acid. The chemical structures of pink-red pigments from leucine, asparagine, glutamine, tyrosine, and cystine also were determined.

Green discolouration (greening) of macerated garlic products is a major concern in the garlic-processing industry, and is caused by reactions between free amino acids and 2-propenyl 1-propenyl (2-Pe/1-Pe) thiosulphinates in the garlic. Efficacy of freeze-dried fresh onion powder that contains the active onion enzyme lachrymatory factor synthase (LFS) to prevent greening in processed garlic was evaluated. LFS converts 1-propenesulphenic acid to the volatile lachrymatory factor (LF). We hypothesised that this conversion would decrease the production of 2-Pe/1-Pe thiosulphinates, and thus, would reduce the subsequent discolouration of the garlic. Cooked onion powder added to fresh garlic, which was equivalent to adding crude 1-PeCSO, resulted in intensified green discolouration and increased 2-Pe/1-Pe thiosulphinate levels. On the other hand, fresh onion powder added to fresh garlic (0.5 g powder to 100 g fresh garlic) prevented greening and decreased the 2-Pe/1-Pe thiosulphinate levels. Similarly, a crude onion enzyme solution prevented greening in a garlic homogenate. The 2-propenyl 2-propenyl thiosulphinate (allicin) content was inconsistently altered by the addition of onion powder. However, the expected production of LF by the fresh onion powder or enzyme solution was not detected by gas chromatography, possibly due to changes in the sample matrix. This method using fresh onion powder is an effective technique for preventing greening of fresh garlic that does not use artificial food additives or cause safety concerns.

BACKGROUND: Lachrymatory factor (LF) synthase in onion bulbs reacts with S-1-propenyl-L-cysteine sulfoxide (1-PeCSO), a key compound in garlic greening. In this study, freeze-dried onion powder containing LF synthase was used in treatments to control garlic greening. Prior to the use of freeze-dried onion powder to treat greening garlic bulbs, model reactions were conducted to confirm the reactivity of 1-PeCSO in onion bulbs to garlic greening. RESULTS: While pink pigments were generated from 1-PeCSO, green pigments were produced from the combination of 1-PeCSO and S-2-propenyl-L-cysteine sulfoxide (2-PeCSO). However, pigments were formed in the systems containing 1-PeCSO, amino acid and alliinase. Even non-greening garlic bulbs stored at 20 °C turned green with the reaction of 200 g L−1 1-PeCSO; therefore 1-PeCSO isolated from onion bulbs had the same role as 1-PeCSO in garlic bulbs in terms of greening. Onion bulbs turned green after the addition of 600 g L−1 2-PeCSO. The addition of freeze-dried onion powder inhibited garlic greening, and treatment with 15 g kg−1 onion powder gave the best storage stability of crushed garlic bulbs. CONCLUSION: The addition of freeze-dried onion powder inhibited the greening in crushed garlic bulbs, and treatment with 15 g kg−1 onion powder gave the best storage stability of crushed garlic bulbs. Copyright © 2011 Society of Chemical Industry

Globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] has been recently introduced as a specialty crop in southwest Texas. Marketable yield, yield components, quality, and phenolic compounds of artichoke heads were investigated in response to three irrigation [50%, 75%, and 100% crop evapotranspiration (ETc)] regimes and four nitrogen (0 to 10, 60, 120, and 180 kg·ha−1) rates under subsurface drip irrigation. Field experiments were conducted over three seasons (2005–2006, 2006–2007, and 2007–2008) at Uvalde, TX. Irrigation was more effective than nitrogen (N) rates to optimize crop yield and head quality. Marketable yields significantly increased at 100% ETc compared with 75% and 50% ETc, whereas a 20% to 35% yield reduction occurred at 50% ETc across seasons. This yield reduction was associated with a decrease in both number of marketable heads and head weight and with reductions in plant physiological responses as measured in the last season. The lack of yield responses to N rates was in part the result of high pre-plant soil NO3-N and NH4-N levels. Total phenolics and chlorogenic acid of artichoke heads increased as the harvesting season progressed and were highest at 50% ETc during mid- and late harvests in one season. Based on these results, we estimate that under these environmental conditions, ≈700 mm (for a bare soil system) of water inputs and 120 kg·ha−1 or less of N (rate depending on soil available N) appear sufficient to obtain high marketable yields, superior size, and nutritional head quality of artichokes.

In order to implement reliable marker-assisted selection systems for the restorer-of-fertility locus (Ms) in onions (Allium cepa L.), simple PCR-based codominant markers linked to the Ms locus were developed. Based on the EST probe sequences of previously reported RFLP markers, full-length genomic sequences of the gene encoding putative oligopeptide transporter (OPT) was obtained by RACE. The first intron contained two 108 and 439-bp indel polymorphisms between the two Ms allele-linked OPT alleles. A simple PCR marker for OPT was developed by designing a primer pair on the flanking regions of the 108-bp indel which is created by two tandem repeats. The second simple PCR marker was developed from the EST probe encoding photosystem I subunit O (PsaO). Two 14 and 39-bp tandem repeats were identified from the 5′ upstream sequences of the PsaO-coding gene, which were isolated by genome walking. Three different compositions of these tandem repeats were identified from diverse onion germplasm. A primer set binding to the flanking sequence of these polymorphic repeats was used to amplify three different marker haplotypes. The OPT marker was tightly linked to the Ms locus at a distance of 1.5 cM, but the analysis of the linkage relationship showed little linkage disequilibrium between the marker and the Ms locus. Even so, these simple PCR markers are valuable tools for the marker-assisted selection of segregating individuals in onion F1 hybrid breeding programs.

Onion pungency is commonly measured on absorbency of the wine pink color that results from adding NaOH to the heated mixture of dinitrophenylhydrazine (DNPH) and onion juice. However, significant variation exists among several modifications of the original Schwimmer and Weston (SW) method. We observed differences in pyruvic acid concentrations of 20%-30% between our automated method and a batch method with manual absorbency readings. To determine the source of the differences, we examined the heating time and waiting time of the sample-DNPH mixtures and found no differences. The differences were caused by differential color degradation between the pyruvic acid standards and onion juice samples. These differences could be minimized by reading the absorbency within 1 min of NaOH addition. Using this information, we devised the one-by-one method to control the reading time at 30 s. We compared 5 different analysis methods of 40 onion samples representing 4 onion colors. The automated, high-performance liquid chromatography, and SW methods had similar results, with only about a 5% difference. However, the batch method resulted in differences of approximately 24% as compared to the automated method. The one-by-one method produced very comparable results, within 5%, to the automated method. By modifying the procedure to ensure a uniform and fast reading time, we increased the consistency between the pungency analysis methods. Therefore, fast and uniform absorbency reading time is essential for an accurate measurement of pungency in undiluted onion juice.

This study was performed to purify and quantify quercetin glycosides (QG) and aglycone (free) quercetin (Q) in 6 selected onion cultivars and to compare analytical approaches based on high-performance liquid chromatography (HPLC) and spectrophotometry for the quantification of total quercetin (TQ) concentrations. Individual mono- and di-glycoside Q compounds were purified using a semipreparative HPLC and identified by comparing spectral data and by confirming corresponding peaks of QG and Q after incomplete enzyme-hydrolysis. Purified QG were quantified as Q by enzyme-hydrolysis/HPLC. TQ concentrations obtained from 20 onion bulbs with enzyme-hydrolysis/HPLC, no-hydrolysis/HPLC, and a spectrophotometric method without prior hydrolysis were significantly correlated (r(2)= 0.99) and were about 15% higher, identical, or 10% less than those concentrations by a standard acid-hydrolysis/HPLC method, respectively. During enzyme-hydrolysis of onion extracts, progressive reduction of the QG and formation of the corresponding mono-glycosides and Q were monitored using an analytical HPLC. TQ ranged from 83 to 330 microg/g F.W. in 6 selected cultivars of long-day or short-day onions. Q3,4'G and Q4'G were the 2 major compounds and comprised approximately between 94% and 97% of TQ in onions.

Sulfur (S) nutrition has a strong influence on onion pungency, and the production of sweet onions in the high-sulfur soil of Texas is a challenge to growers. This study was performed to determine the effects of S applications to fields already having sufficient levels of soil S on pungency and related compounds in four shortday onion cultivars. The onion cultivars ‘Cougar’, ‘Legend’, ‘Texas Early White’, and ‘Texas Grano 1015Y’ were grown in three commercial fields at Edinburg, Mercedes, and Weslaco of the Rio Grande Valley of South Texas with applications of sulfur at 0, 13, and 26 kg S/ha. Pyruvic acid, bulb weight, extractable S in soil and total S in bulb, soluble solids content (SSC), flavor precursor compounds [also called S-alk(en)yl- l -cysteine-sulfoxides (ACSOs)], and total sugars were measured. The pyruvic acid level of onions was not increased by the S applications and showed no significant correlation with soil S levels in any of the cultivars at locations having 30 or 235 ppm S. The SSC, total S in bulbs, total sugars, and total ACSO content also showed no correlation with the S applications and soil S levels. Onion pungency and content of flavor precursor compounds were significantly influenced by cultivar and cultivar × location interaction. We conclude that onion pungency is not increased by application of extra S fertilizer to commercial fields already containing sufficient levels of soil sulfur.

This study was conducted to characterize shortday onions of 3 pungency levels with regard to the composition of flavor related compounds. A total of 9 onion breeding lines/cultivars were selected, per each of low, medium, and high pungency level, with pyruvic acid contents of 1.9 to 2.8, 4.8 to 5.4, and 7.2 to 8.3 micromoles/mL, respectively. The contents of flavor precursors (S-1-propenyl-L-cysteine sulfoxide [1-PeCSO] and S-methyl-L-cysteine-sulfoxide [MCSO]), free amino acids, free sugars, soluble solids (SSC), and total sulfur (S) in onion bulbs were measured. The flavor precursor contents ranged from 0.03 to 0.16 mg/g fresh weight (FW) for MCSO, 0.07 to 0.65 mg for 1-PeCSO, and 0.12 to 0.77 mg in total, and precursor contents increased with the pungency levels. Onions of different pungency levels did not differ in the contents of individual or total free amino acids, and the most abundant amino acids were glutamine and arginine. The total sugar contents ranged from 50 to 75 mg/g FW, and total S contents (3.5 to 5.1 mg/g dry weight) were not correlated with the pungency levels. However, pungency levels were correlated inversely with bulb weight and positively with SSC, presumably by the effect of dilution. This study indicates that onion pungency is primarily determined by the content of flavor precursor compounds and not by total S, total sugars, or individual/total free amino acids in shortday bulbs.

Phytochemical levels in fruits and vegetables can be affected by several postharvest factors. In the present study, the effect of electron-beam (E-beam) irradiation was studied on grapefruit bioactive compounds. 'Rio Red' and 'Marsh White' grapefruits were irradiated with E-beam at 0, 1.0, 2.5, 5.0, and 10.0 kGy. Changes of various bioactive compounds, such as vitamin C, flavonoids, carotenoids, furocoumarins, and limonoids, were measured. The acidity decreased slightly with an increasing E-beam dose, whereas the total soluble solids were increased. Irradiation did not affect the vitamin C content at 1 kGy; however, doses beyond 1 kGy significantly reduced the vitamin C content. Lycopene and beta-carotene did not change significantly from the irradiation. Lycopene levels decreased as the E-beam dose increased, while the beta-carotene content slightly increased. Dihydroxybergamottin levels exhibited a decreasing trend, while the bergamottin content did not change. Naringin, a major flavonoid of grapefruit, showed a significant increase over the control at 10 kGy in both 'Rio Red' and 'Marsh White'. Nomilin continued to decrease with an increasing dose of E-beam irradiation, while limonin levels remained the same at all of the doses. Low-dose E-beam irradiation has very little effect on the bioactive compounds and offers a safe alternative to existing postharvest treatments for the disinfection and decontamination of grapefruits.

Grapefruits were found to contain D-glucaric acid, which has anticancer properties. In the present investigation, a method has been developed for the quantification of D-glucaric acid in grapefruit by high-performance liquid chromatography (HPLC) using a simple isocratic mobile phase with detection at 210 nm. Grapefruit samples were homogenized, centrifuged and filtered through a 0.45 microm membrane and injected into a HPLC system. The developed method was used for the quantification of D-glucaric acid in nine widely used grapefruit varieties. Furthermore, the identity of D-glucaric acid was confirmed by mass spectra. Seasonal variation of D-glucaric acid within the individual varieties were also measured in fruits harvested during November, February and May. The overall trend of D-glucaric acid level was increased from early to late season fruits. The developed method has a sensitivity of D-glucaric acid as low as 0.05 microg with an accuracy and precision >95%. This method was found to be simple, fast, accurate and reproducible. Moreover, the identity of D-glucaric acid was confirmed by mass spectra. Additionally, the labor intensity and cost of sample preparation were greatly reduced as compared to reported methods. This is the first report on quantification of D-glucaric acid in different varieties of grapefruits from three harvesting sessions.

Our objectives were to identify RAPD and andromonoecious (a) markers associated with QTL for sucrose using bulked segregant analysis in an F 2 population from the melon (Cucumis melo L.) cross of 'TAM Dulce' (high sucrose) × TGR1551 (low sucrose) in a greenhouse experiment, and confirm the association of RAPD and a markers with sucrose QTL in an F 2 population from the different cross of 'Deltex' (high sucrose) × TGR1551 in a field experiment. Continuous distributions for sucrose were observed in the F2 populations indicating quantitative inheritance for the trait. A significant positive correlation was found between sucrose and total soluble solids (TSS). Nine RAPD markers were detected to be significantly associated with QTL for sucrose in the F2 population of the 'TAM Dulce' × TGR1551 cross in the greenhouse based on simple linear regression. Five unlinked markers associated with QTL were significant in a stepwise multiple regression analysis where the full model explained 39% of the total phenotypic variation for sucrose. Three to five of the nine RAPD markers were also observed to be significantly associated with QTL for glucose, fructose and TSS, respectively, suggesting that in this cross four sugar traits are controlled by the same QTL. Four RAPD markers were confirmed in the F 2 population of the 'Deltex' × TGR1551 cross in the field to be consistently associated with sucrose QTL. A significant association of a with sucrose was consistently expressed in our populations under greenhouse and field environments.

Bioactive compounds in citrus fruits have been shown to be protective against chronic diseases such as cancer and heart disease, but their levels may be affected by postharvest treatments such as storage and irradiation. In this study, grapefruits were exposed to gamma irradiation at 0, 150 and 300 Gy and then stored at 10 °C for 36 d, followed by an additional 20 d at 20 °C. Flavonoid content, terpenoid content, quality (acidity and total soluble solids) and phenylalanine ammonia-lyase (PAL) activity were evaluated at regular intervals during storage. Irradiation and storage affected ( P ⩽ 0.05) the levels of bioactive compounds in grapefruit; however, the effect of storage was prominent. Irradiation differentially affected the flavonoid content of pulp and peel. Fruits exposed to 300 Gy had higher ( P ⩽ 0.01) narirutin content in peel compared to control fruits at 12 and 56 d after storage. While storage increased the d -limonene and myrcene content in all treatments, control fruit had higher terpenoid content at the end of the storage. PAL activity was found to be in traces in the peel. In general, irradiation or storage had no considerable effect on total soluble solids; however, acidity decreased ( P ⩽ 0.05) with storage.

Introduction of artichokes in the Wintergarden of Texas depends on the development of strategies that will overcome limiting climatic conditions for optimal growth. Irrigation efficiency has been critical in this area due to strict restrictions on water application and regulations of underground aquifer resources. We evaluated cultivars with different bolting requirements at two planting dates and irrigation rates. Transplants of five seed propagated cultivars (Emerald, Experimental Red, Imperial Star, Green Globe, and Purple Romagna) were planted in the field on 27 September and 3 December 2004, and evaluated at 100% and 75% crop evapotranspiration rates (ETc) at Uvalde, Texas. Harvests started on 24 March and 21 April 2005 for the September and December planting dates, respectively. Yield increased over 4-fold for the September compared to the December planting date. Irrigation rates did not affect yield, water use efficiency or head quality. Cultivars Emerald, Imperial Star and Experimental Red were earlier than Green Globe and Purple Romagna. The best yield was achieved with cv. Imperial Star. Fiber, nitrogen, and phenolic compounds concentration depended on cultivar. As harvesting season progressed nitrogen concentration decreased, whereas total fibers content increased.

This study was conducted to determine the effects of genetic and environmental factors on onion pungency, estimated as pyruvic acid levels. Genetically identical clones were grown at three different field locations and in a greenhouse. Onion pungency was significantly influenced by clone type, location, and their interaction. Genetic differences were the major determining factor of onion pungency (81.3% of total variation). Location, including all environmental factors, and the clone × location interaction comprised 11.4% and 7.3% of the total variation, respectively. The magnitude of the pungency difference among field-grown onions was about 1.5 μmol/ml. The pungency levels were not positively correlated with soil sulfur nutrition levels, which ranged from 16 to 97 ppm. Within clones, onion pungency levels were loosely inversely correlated with increasing bulb weight. The clones proved to have the most uniform pungency (8% CV), followed by hybrids (10.6% CV) and open-pollinated cultivars (21.3% CV). We have demonstrated that genetic factors were determinant of onion pungency. Environmental factors influenced pungency to a lesser degree. Therefore, choosing cultivars with low pungency, ideal growing environments and proper sulfur nutrition control, are key factor in producing sweet onions.

Our objectives were to identify randomly amplified polymorphic DNA (RAPD) markers associated with quantitative trait loci (QTL) for sucrose, total soluble solids (TSS), and sucrose percentage of total sugars (SPTS) using bulked segregant analysis in an F2 population from the melon (Cucumis melo L.) cross of `TAM Dulce' (high sugars) × TGR1551 (low sugars) in a greenhouse experiment, and confirm the associations of RAPD markers with QTL for these sugar traits in an F2 population from the different cross of `Deltex' (high sugars) × TGR1551 in a field experiment. Continuous distributions for sucrose, TSS, and SPTS were observed in the F2 populations indicating quantitative inheritance for the traits. Significant positive correlations were found between sucrose and TSS or SPTS. Nine RAPD markers were detected to be significantly associated with QTL for sucrose in the F2 population of the `TAM Dulce' × TGR1551 cross in the greenhouse based on simple linear regression. Five unlinked markers associated with QTL were significant in a stepwise multiple regression analysis where the full model explained 39% of the total phenotypic variation for sucrose. Five and seven of the nine RAPD markers associated with QTL for sucrose were also observed to be significantly associated with QTL for TSS and SPTS, respectively, suggesting that in this cross three sugar traits are controlled by the same QTL. Five RAPD markers were confirmed in the F2 population of the `Deltex' × TGR1551 cross in the field to be consistently associated with QTL for three sugar traits. Significant associations of andromonoecious (a) with both sucrose and TSS were consistently expressed in our populations under greenhouse and field environments. These RAPD and floral markers associated with the sugar synthesis QTL identified and confirmed here could be useful in melon breeding for improving the mature fruit sweetness.

Bulb color in onions (Allium cepa) is an important trait, and homogenous red coloration is desirable in red onion cultivars. The gene encoding anthocyanin synthase (ANS) is required for anthocyanin biosynthesis in onions. We have previously described three different alleles of the ANS gene. Here we report identification of the fourth allele of ANS, ANS-h1, found in a dark red doubled haploid line. ANS-h1 is similar to a non-functional allele found in Brazilian yellow cultivars except that it has several point mutations and indels throughout the promoter and coding regions, none of which are predicted to inactivate enzymatic activity. F2 and backcross populations originating from the crosses between wild-type (ANS-L) allele-containing red and pink (ANS-p) allele-containing white or yellow parents show a discrete segregation ratio of 3 red to 1 light pink, indicating that the wild-type allele is completely dominant over the pink allele. In contrast, segregating populations derived from the crosses between ANS-h1 allele-containing red and the same white or yellow parents show a gradient of red intensity from light pink to dark red, suggesting that other genetic factors may affect expression of ANS-h1. A newly developed PCR-based marker and two previously developed markers for allelic selection of the ANS gene were used to examine allele composition in fifty-six breeding lines and commercial cultivars. Most lines are heterogeneous for the ANS gene with two or three alleles detected. The frequency of the pink allele is low in red breeding lines, but it is predominant in white and yellow lines.

Citrus flavonoids have been shown to possess biological activities such as anti-inflammatory properties, cholesterol lowering and immune system modulation. In this study, 12 made-from-concentrate (MFC) and 14 not-from-concentrate (NFC) orange juices, and five NFC grapefruit juices available in the US market were analyzed for their flavonoid content by reverse phase HPLC. Individual and total flavonoid content was determined for all of the brands. The correlation between flavonoid content (mg) and price (US dollar) per unit volume of orange and grapefruit juices were also evaluated. Significant differences ( P ⩽ 0.05 ) among the brands and within the brand were observed for all of the prominent flavanone glucosides. Within the brand, juice types containing added antioxidant vitamins C and E were not superior in flavonoid content compared to orange juice types devoid of added antioxidant vitamins. Total flavonoid content of MFC orange juices (53 mg/100 mL; n = 12 ) was significantly ( P ⩽ 0.05 ) higher than NFC orange juices (36.5 mg/100 mL; n = 14 ). Hesperidin was found to be the major flavonoid followed by narirutin and didymin in orange juice. Naringin, narirutin, and poncirin were the major flavonoids in all brands of grapefruit juices. The concentration of didymin was considerably higher in NFC orange juices compared to MFC orange juices. Interestingly, no correlation was observed between price and the total flavonoid content of MFC orange juices and NFC grapefruit juices. However, a significant negative correlation ( r = - 0.49 ; P = 0.001 ) was observed for NFC orange juices. This study provides valuable information on flavonoid composition of orange and grapefruit juices commonly available in the US market.

Peppers ( Capsicum spp.) were grown for phytochemical analyses at three different locations including a greenhouse at College Station and field plots at Uvalde and Weslaco, Texas. Cultivar effects were significant at each location for all compounds. The best sources of β-carotene were mature greenhouse-grown fruit of Fidel (23.7 μg/g) and C 127 (22.3 μg/g). Mature greenhouse fruit of Tropic Bell (10.1 μg/g) and PI 357509 (9.2 μg/g) had high lutein, but Uvalde field-grown mature fruit of these lines were low in this compound, (1.4 and 0.5 μg/g, respectively). MJ 201 fruit had the highest zeaxanthin levels (10 μg/g) at both College Station and Uvalde. The best sources of quercetin over all locations were the yellow wax types, Banana Supreme (186 μg/g), PI 357509 (86 μg/g) and Rio Grande Gold (26 μg/g). Fidel (37 μg/g) and Banana Supreme (21.5 μg/g) were the best sources of luteolin. Immature fruit generally contained lower levels of lutein and xeaxanthin than mature, colored fruit. These differences were not always statistically significant. Greenhouse-grown peppers at College Station contained more carotenoids than the field-grown peppers in Uvalde and Weslaco, but there were no significant differences among locations for flavonoid concentrations. Several good candidate parents were identified for the breeding program to develop novel pepper varieties with increased health benefits. Families of these varieties are currently being examined to assess the impact of specific environmental factors and identify genes involved in regulating synthesis of these beneficial phytochemicals.

In onions (Allium cepa), a variety of bulb colors exist ranging from white, yellow, to red, with different intermediate shades. In order to identify the function of the basic color factor, the C locus, which is required for any color production, a candidate gene approach was attempted utilizing anthocyanin synthesis pathway genes. RT-PCR was carried out to examine differential expression of the genes involved in the anthocyanin synthesis pathway among four different bulb colors: recessive white, dominant white, yellow, and red. The transcription of two homologous chalcone synthase (CHS) genes (CHS-A and CHS-B) was significantly reduced in both dominant and recessive white onions. The reduced transcription of CHS genes was also observed in white, but not yellow, F2 plants originating from the cross between white and yellow onions. Single nucleotide polymorphism (SNP) markers tagging parental alleles of CHS genes were utilized to determine whether the reduced transcription of CHS genes was caused by mutations in CHS genes or other regulatory genes. In the F2 populations originating from the cross between recessive white and yellow or red parents, the SNP markers tagging two parental alleles of the CHS-A and CHS-B genes did not co-segregate with the genotype of the C locus. These results suggest that the basic color factor is likely to be a regulatory gene controlling CHS gene transcription.

Unusual gold-colored onions were selected from a F3 family originating from a cross between US-type yellow and Brazilian yellow onions. HPLC analysis showed that the gold onions contained a significantly reduced amount of quercetin, the most abundant flavonoid in onions. This result indicated that an early step in the flavonoid biosynthesis pathway might be abnormal in these onions. The expression of flavonoid synthesis genes isolated from onions was examined in gold onions and compared to that in onions of other colors by RT-PCR. The results showed that all genes were transcribed in gold onions as in red onions. In order to identify any critical mutations in flavonoid synthesis genes encoding enzymes involved in early steps of the pathway, the genomic sequence of chalcone isomerase (CHI) was obtained. A premature stop codon and a subsequent single base-pair addition causing a frameshift were identified in the coding region of the CHI gene in the gold onions. Co-segregation of the mutant allele of the CHI gene and the gold phenotype was investigated in the original F2 segregating population. Genotyping of three color groups (red, yellow and gold) of F2 onions revealed perfect co-segregation of the mutant CHI allele with the gold phenotype. All tested gold F2 onions were homozygous for the mutant CHI allele. This perfect co-segregation implies that the presence of a premature stop codon in the gold CHI gene results in an inactive CHI. Inactivation of CHI results in a block in the flavonoid biosynthesis pathway and the accumulation of chalcone derivatives, including a yellow pigment which might be responsible for the gold color in onions.

Onion pungency is estimated by measuring the pyruvic acid content in juice extracted from fresh tissues. We compared pyruvic acid content and its variation in the juices extracted by the pressing, maceration, blending with no water, or blending with water (blend/water) methods.There were considerable differences in the pyruvic acid content and coefficient of variation (CV) among these methods, and there was an interaction between the onion cultivars and the juice extraction methods. The pressing method showed over 30% CV in the quartered or composite samples. The blend/water method showed the greatest pyruvic acid content in the shortday-type ('TG1015Y' and 'Texas Early White') onions, while the pressing method showed the greatest pyruvic acid content in the longday-type onions. The blend/water method, which gave ratios between 1:1 and 1:4 (w/w), showed the same pyruvic acid content. The blending (no water) method had the highest correlation, followed by the maceration method. The lowest correlations were found with the pressing method and the blend/water method.Complete homogenisation of tissues with 1:1 or greater ratios of water was necessary for the maximum consistency and full development of the pyruvic acid reaction for onion pungency measurement.

A method used for anthocyanin measurement in cranberry resulted in a problem of interference by carotene in purple carrot extracts. We developed a method suitable for a purple color carrot breeding program. The new method includes a three step process: (1) extraction of anthocyanins using a small amount of acidified ethanol (95% ethanol in 1.5 N HCl); (2) removal of carotenoids present in the extract; and (3) measurement of total anthocyanins with a spectrophotometer. The purple colored carrots analyzed contained around 38–98 mg anthocyanin per 100 g fresh weight. The new method can be efficiently used in a breeding program for the development of purple colored carrots for nutritional benefits and a source of a natural pigment.

Background pyruvic acid concentration is a critical factor to determine onion pungency but greatly different values have been reported. This study was initiated to measure accurate background pyruvic acid levels in onion cultivars, other Allium species, and non-Allium vegetables using an HPLC method. A microwaving time of 2 min per 100 g was sufficient to deactivate alliinase and further degradation of pyruvic acid was not observed up to 6 min. Five percent trichloro acetic acid was suitable for both fresh and frozen tissues, while 80% ethanol did not stop the alliinase activity completely. The background pyruvic acid concentrations in various onion cultivars were less than 0.34 μmol ml−1, while garlic and onion sprouts were 0.84–0.95 μmol ml−1. Non-Allium vegetable also showed very low levels (0.09–0.34 μmol ml−1) of pyruvic acid in the microwaved tissues. This study confirmed that background pyruvic acid levels in onion were minimal and could be disregarded in a routine analysis. Previous reports of high levels of the background pyruvic acid may need to be reviewed for accuracy.