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A study examines whether the flavor of broccoli cultivars is caused by its glucosinolate content. The aroma and flavor of several broccoli are examined.

Pumpkins, a subgroup of the domesticated Cucurbita species, have been reported to range in fruit type (related to size) from miniature (<100 g) to jumbo (>273 kg). In order to obtain a wide range of fruit types it is hypothesised that all potential factors affecting fruit type must be used. One factor that is often overlooked in plant studies is genome size. In various plant species, genome size variation has been associated with characteristics such as cell size, plant size and flowering time. Such characteristics are referred to as nucleotypic parameters. In order to determine if nucleotypic selection is occurring in pumpkin, 17 varieties were analysed for genome size variation in two separate experiments. The species selected encompass the total range of fruit types reported in pumpkin. Significant nuclear DNA content variation was observed in pumpkin. There was no significant correlation between genome size and fruit type. In fact, the miniature pumpkin types were found to have the same genome size as the jumbo pumpkin types. In addition, a positive correlation between genome size and stomata length (an estimate of cell size in plants) was observed. Both the miniature and jumbo types were observed to have the smallest genome size and the smallest cell size. Thus, nucleotypic selection does appear to occur in pumpkin and appears to be involved in determining fruit type, although it may not be the only factor involved. [ABSTRACT FROM AUTHOR]

The activities of 5′-methylthioadenosine (MTA) nucleosidase (EC 2.2.2.28) and 5-methylthioribose (MTR) kinase (EC 2.7.1.100) were related to changes in ethylene biosynthesis in tomato (Lycopersicon esculentum Mill. cv. Rutgers) and cucumber (Cucumis sativus Mill. cv. Poinsett 76) fruit following wounding and chemically induced stresses. Stress ethylene formation in wounded tomato and cucumber tissue continued to increase after wounding, reached its peak by 3 h, and then declined. The activities of MTA nucleosidase and MTR kinase increased parallel to stress ethylene in both tissues. At peak ethylene formation, MTA and MTR kinase activities were 2- to 4-fold higher in wounded than in intact tissue. Wounded, mature-green tomato tissue treated with specific inhibitors of MTA nucleosidase and MTR kinase showed a significant reduction in the activities of these enzymes, which was concomitant with a decline in stress ethylene biosynthesis. When mature-green tomato discs were infiltrated with [14CH3] MTA and wounded, radioactive MTR and methionine were formed. Incubation of mature-green tomato discs with Cu2+ and Li+ in the presence of kinetin increased ethylene biosynthesis. MTA nucleosidase activity was higher than that of the control in the presence of Cu2+ but not in the presence of Li+, while MTR kinase activity was lower than that of the control in both Cu2+ and Li+ treatments. Data indicate that MTA nucleosidase and MTR kinase are required for wound-induced ethylene biosynthesis but not for chemical stress-induced ethylene by Cu2+ or Li+ treatments. [ABSTRACT FROM AUTHOR]

The aim of this cross-sectional study was to assess safe food handling practices, food safety knowledge, and adherence to implementation of Hazard Analysis and Critical Control Point among 53 food safety managers working in randomly selected food service establishments in Qatar. Face-to-face interviews with the managers at each participating food service establishment were conducted using a survey consisting of 40 questions in October-December 2015. In addition to the survey questionnaire, a checklist was used to determine the implementation of Hazard Analysis and Critical Control Point by observing actual practices applied at each food service establishment. About 66 and 68% of managers had college degree and were trained on Hazard Analysis and Critical Control Point, respectively. Results also showed that casual sit-in and fine dine-in restaurants were the only food service establishments that consistently kept records on safe food handling practices (100%), followed by fast-food food service establishments (36%). Managers' training and education level were highly correlated with the probability of their employees receiving food safety training. This first assessment on food safety knowledge and practices in Qatar demonstrated that training and education are important factors that directly impact the food safety culture in food service establishments. These findings may help government agencies establish guidelines for compulsory on-site training of food handlers for effective food safety practices in food service establishments in Qatar where the fast growing demography has led to a rapid growth in food service establishment in different cuisines leading to heterogeneity in food safety practices.

Influence of Refractance Window™ Drying (RWD), a novel contact drying method, on carotenoids, capsaicinoids, Retinol Activity Equivalent (RAE) and Scoville Heat Unit (SHU) of paprika (Cv., Jalapeno) was investigated in comparison with freeze drying (FD), oven drying (OD), and natural convective drying (NCD) methods. Eight carotenoids (capsanthin, capsorubin, capsolutein, β-carotene, β-cryptoxanthin, mutatoxanthin, violaxanthin and zeaxanthin) and five capsaicinoid analogues (capsaicin, dihydrocapsaicin, homodihydrocapsaicin, isodihydrocapsaicin, nordihydrocapsaicin) were identified in paprika. All these components were significantly (P<0.05) decreased by the RWD, FD and OD methods. However, due to ongoing synthesis, the NCD method resulted in higher carotenoids, except violaxanthin and mutatoxanthin, and capsaicinoids content than those of the others, even puree. Mutatoxanthin, naturally occurring pigment in red pepper, could only be detected in FD paprika. The highest RAE and SHU values, which were derived from the data of carotenoids and capsaicinoids, respectively, were also determined in NCD paprika., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

An extraction and preparative HPLC method has been devised to simultaneously purify sulforaphane and sulforaphane nitrile from the seed of Brassica oleracea var. italica cv. Brigadier. The seed was defatted with hexane, dried, and hydrolyzed in deionized water (1:9) for 8 h. The hydrolyzed seed meal was salted and extracted with methylene chloride. The dried residue was redissolved in a 5% acetonitrile solution and washed with excess hexane to remove nonpolar contaminants. The aqueous phase was filtered through a 0.22-microm cellulose filter and separated by HPLC using a Waters Prep Nova-Pak HR C-18 reverse-phase column. Refractive index was used to detect sulforaphane nitrile, and absorbance at 254 nm was used to detect sulforaphane. Peak identification was confirmed using gas chromatography and electron-impact mass spectrometry. Each kilogram of extracted seed yielded approximately 4.8 g of sulforaphane and 3.8 g of sulforaphane nitrile. Standard curves were developed using the purified compounds to allow quantification of sulforaphane and sulforaphane nitrile in broccoli tissue using a rapid GC method. The methodology was used to compare sulforaphane and sulforaphane nitrile content of autolyzed samples of several broccoli varieties.

Cruciferous vegetables contain high levels of vitamins that can act as antioxidants, compounds that may protect against several degenerative diseases. The edible portions of 50 broccoli and 13 cabbage, kale, cauliflower, and Brussels sprouts accessions were assayed to determine variation in alpha-carotene, beta-carotene, alpha-tocopherol, gamma-tocopherol, and ascorbate contents within and between subspecies of Brassica oleracea. Ascorbate content was estimated in fresh samples using HPLC. Tissues for carotene and tocopherol analysis were lyophilized prior to extraction. Carotene and tocopherol concentrations were simultaneously measured using a reverse phase HPLC system. Results indicate that there is substantial variation both within and between subspecies. Kale had the highest levels of vitamins, followed by broccoli and Brussels sprouts with intermediate levels and then by cabbage and cauliflower, with comparatively low concentrations. Variability in vitamin content among the broccoli accessions suggests that potential health benefits that accrue with consumption are genotype dependent.

Glucosinolates were evaluated in 5 groups and 65 accessions of Brassica oleracea (50 broccoli, 4 Brussels sprouts, 6 cabbage, 3 cauliflower, and 2 kale) grown under uniform cultural conditions. Glucosinolates and their concentrations varied among the different groups and within each group. The predominant glucosinolates in broccoli were 4-methylsulfinylbutyl glucosinolate (glucoraphanin), 3-butenyl glucosinolate (gluconapin), and 3-indolylmethyl glucosinoate (glucobrassicin). Glucoraphanin concentration in broccoli ranged from 0.8 micromol g(-1) DW in EV6-1 to 21.7 micromol g(-1) DW in Brigadier. Concentrations of the other glucosinolates in broccoli varied similarly over a wide range. In Brussels sprouts, cabbage, cauliflower, and kale, the predominant glucosinolates were sinigrin (8.9, 7.8, 9.3, and 10.4 micromol g(-1) DW, respectively) and glucobrassicin (3.2, 0.9, 1.3, and 1.2 micromol g(-1) DW, respectively). Brussels sprouts also had significant amounts of gluconapin (6.9 micromol g(-1) DW). Wide variations in glucosinolate content among genotypes suggest differences in their health-promoting properties and the opportunity for enhancement of their levels through genetic manipulation.

The recycling of 5-methylthioribose (MTR) to methionine in avocado (Persea americana Mill, cv Hass) and tomato (Lycopersicum esculentum Mill, cv unknown) was examined. [(14)CH(3)]MTR was not metabolized in cell free extract from avocado fruit. Either [(14)CH(3)]MTR plus ATP or [(14)CH(3)]5-methylthioribose-1-phosphate (MTR-1-P) alone, however, were metabolized to two new products by these extracts. MTR kinase activity has previously been detected in these fruit extracts. These data indicate that MTR must be converted to MTR-1-P by MTR kinase before further metabolism can occur. The products of MTR-1-P metabolism were tentatively identified as alpha-keto-gamma-methylthiobutyric acid (alpha-KMB) and alpha-hydroxy-gamma-methylthiobutyric acid (alpha-HMB) by chromatography in several solvent systems. [(35)S]alpha-KMB was found to be further metabolized to methionine and alpha-HMB by these extracts, whereas alpha-HMB was not. However, alpha-HMB inhibited the conversion of alpha-KMB to methionine. Both [U-(14)C]alpha-KMB and [U-(14)C]methionine, but not [U-(14)C]alpha-HMB, were converted to ethylene in tomato pericarp tissue. In addition, aminoethoxyvinylglycine inhibited the conversion of alpha-KMB to ethylene. These data suggest that the recycling pathway leading to ethylene is MTR --> MTR-1-P --> alpha-KMB --> methionine --> S-adenosylmethionine --> 1-aminocyclopropane-1-carboxylic acid --> ethylene.

Three compounds known to inhibit ethylene synthesis and/or action were compared for their ability to delay senescence and abscission of bean explants (Phaseolus vulgaris L. cv Contender). Aminoethoxyvinyl-glycine (AVG), AgNO(3), and sodium benzoate were infiltrated into the petiole explants. Their effect on abscission was monitored by measuring the force required to break the abscission zone, and their effect on senescence was followed by measuring chlorophyll and soluble protein in the distal (pulvinus) sections. AVG at concentrations between 1 and 100 micromolar inhibited ethylene synthesis by about 80 to 90% compared to the control during sampling periods of 24 and 48 hours after treatment. This compound also delayed the development of abscission and senescence. Treatment with AgNO(3) at concentrations between 1 and 100 micromolar progressively reduced ethylene production, but to a lesser extent than AVG. The effects of AgNO(3) on senescence and abscission were quite similar to those of AVG. Sodium benzoate at 50 micromolar to 5 millimolar did not inhibit ethylene synthesis during the first 24 hours, but appreciably inhibited ethylene synthesis 48 hours after treatment. It also delayed the development of abscission and senescence. The effects of AVG, Ag(+), and sodium benzoate suggest that ethylene could play a major role in both the senescence induction phase and the separation phase in bean explants.

Putrescine (Put) increased 68% in lemon (Citrus limon (L.) Burm. f. cv Bearss) flavedo, 39% in grapefruit (C. paradisi Macf. cv Marsh) flavedo, 49% in grapefruit juice, and 149% in pepper (Capsicum annuum L. cv Early Calwonder) pericarp when fruits were stored at chilling temperatures. In lemon flavedo, the coefficient of correlation (r(2)) between Put concentration with severity of chilling was 0.90 and Put levels almost doubled; the injury index going from 1 to 2 units. Pepper pericarp, which was the most chilling-sensitive tissue tested (injury index going from 1 to 3.8 units), showed the greatest difference in Put accumulation (166 to 413 nanomoles per gram fresh weight) between storage temperatures of 7.2 and 1 degrees C. The least difference (338 to 470 nanomoles per gram fresh weight) was found in grapefruit flavedo between storage temperatures of 15.5 and 4.4 degrees C; the injury index going from 1 to 1.3 units.

Concentrations of polyamines (PA) and the activities of the PA-synthesizing enzymes ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) extracted from the mesocarp tissue of avocado (Persea americana Mill, cv ;Simmonds') fruits at different stages of development were compared with DNA content and the activities of 5'-methylthioadenosine (MTA) nucleosidase and 5-methylthioribose (MTR) kinase. Putrescine, spermidine, and spermine were at their peak concentrations during the early stages of fruit development (362, 201, and 165 nanomoles per gram fresh weight, respectively, at 15 days from full bloom), then declined to 30% or less at full maturity. Agmatine showed only a slight change in concentration throughout the fruit development. The activity of ODC, which was low during flowering (8 nmoles per milligram protein per hour), increased more than threefold during the first 2 months then declined at the later stages of fruit development, while ADC activity showed only a slight increase. DNA content followed a similar pattern of change as that of PA and ODC. The decline in DNA and ODC activity suggest a lack of correlation between cell proliferation and PA at the later stages of the avocado fruit development. It is also possible that any cell division which may take place during the latter stages of the fruit development is not sufficient to alter the pattern of PA biosynthesis. MTA nucleosidase and MTR kinase activities increased during the first 15 days of fruit development followed by a slight decline at 60 and 90 days from full bloom. At 120 days (1 month before full maturity) both MTA nucleosidase and MTR kinase activities increased significantly. During maximum ethylene synthesis, MTA nucleosidase and MTR kinase activities were approximately fivefold and eightfold, respectively, higher than during maximum PA synthesis. The data indicate that the MTA molecules produced during PA and ethylene synthesis are actively metabolized to MTR and MTR-1-P, the two intermediates involved in the regeneration of S-adenosylmethionine from MTA. The data also suggest that the PA and ethylene biosynthetic pathways are not actively competing for the same substrates at any given stage of the avocado fruit development and ripening.

5'-Methylthioadenosine (MTA) nucleosidase and 5-methylthioribose (MTR) kinase activities were measured in crude extracts of tomato fruits (Lycopersicon esculentum Mill cv Rutgers) during fruit development and ripening. The highest activity of MTA nucleosidase (1.2 nanomoles per milligram protein per minute) was observed in small green fruits. The activity decreased during ripening; at the overripe stage only 6.5% of the peak activity remained. MTR kinase activity was low at the small green stage and increased thereafter until it reached peak activity at the breaker stage (0.7 nanomoles per milligram protein per minute) followed by a sharp decline at the later stages of fruit ripening. 1-Amino-cyclopropane-1-carboxylic acid (ACC) levels peaked at the red stage, while ethylene reached its highest level at the light-red stage. Several analogs of MTA and MTR were tested as both enzyme and ethylene inhibitors. Of the MTA analogs examined for their ability to inhibit MTA nucleosidase, 5'-chloroformycin reduced enzyme activity 89%, whereas 5'-chloroadenosine, 5'-isobutylthioadenosine, 5'-isopropylthioadenosine, and 5'-ethylthioadenosine inhibited the reaction with MTA by about 40%. 5'-Chloroformycin and 5'-chloroadenosine inhibited ethylene production over a period of 24 hours by about 64 and 42%, respectively. Other analogs of MTA were not effective inhibitors of ethylene production, whereas aminoethoxyvinylglycine showed a 34% inhibition over the same period of time. Of the MTR analogs tested, 5-isobutylthioribose was the most effective inhibitor of both MTR-kinase (41%) and ethylene production (35%).

The polyamines (PA) putrescine (Put), spermidine (Spd), and spermine (Spm) were measured during 3 weeks exposure to cold hardening (15.6 degrees C day and 4.4 degrees C night) and nonhardening (32.2 degrees C day and 21.1 degrees C night) temperature regimes in three citrus cultivars: sour orange (SO) (Citrus aurantium L.), ;valencia' (VAL) (Citrus sinensis L. Osbeck), and rough lemon (RL) (Citrus jambhiri Lush). The changes in PA were compared to the amount of free proline, percent wood kill and percent leaf kill. A 2- to 3-fold increase in Spd concentrations were observed in hardened RL, SO, and VAL leaves compared to nonhardened leaves. Spermidine reached its highest level of approximately 200 nanomoles per gram fresh weight after 1 week of acclimation in both SO and VAL leaves, while RL spermidine content continued to increase up to the third week of acclimation. Spm levels in acclimated VAL and RL leaves increased 1- to 4-fold. However, SO leaves Spm content decreased with acclimation. Putrescine levels in SO and VAL increased 20 to 60% during the first 2 weeks of acclimation then declined after 3 weeks. RL putrescine content was not affected by cold acclimation. The data presented here provided direct relationship between increased Spd concentration and citrus cold hardiness. Free proline was 3- to 6-fold higher in acclimated than in nonacclimated trees. Results also demonstrate that in acclimated versus nonacclimated citrus trees the absolute amount rather than the ratio of increase in free proline is more important in predicting their ability to survive freezing stress.