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BACKGROUND: During the production of fresh-cut products, crops are exposed to wounding stress, and as a stress response, phenolic antioxidants are synthesized. This stress response is elicited by extracellular adenosine triphosphate, released from wounded cells and recognized by receptors of unwounded cells. The phenolic antioxidants produced as a stress response are beneficial for human health. However, a common practice in the fresh-cut industry is the application of washing/sanitizing procedures after cutting. These procedures could be highly detrimental, since they partially remove the wound signal that elicits the biosynthesis of phenolics in plants. In this study, the impact of different washing/sanitizing treatments post-shredding on the wound-induced accumulation of chlorogenic acid (CHA) in carrot was evaluated. Peeled carrots were shredded and dipped in aqueous solutions containing chlorine (100 ppm, 2 min), hydrogen peroxide (1.5%, 2 min) or water (2 min). The content of CHA in treated carrots was evaluated before and after 48 h of storage (19 ± 2 °C). RESULTS: The control carrots sanitized only before peeling and shredding showed 4000% higher content of CHA as compared with time 0 h samples. However, carrots treated with washing/sanitizing procedures post-shredding including water, chlorine and hydrogen peroxide showed a decrease in the accumulation of CHA by 46.9%, 53.6% and 89.9%, respectively. CONCLUSIONS: The results demonstrated that washing/sanitizing procedures applied after fresh-cutting are potentially detrimental to the wound-induced accumulation of health-promoting compounds during storage of fresh produce. Thus, the fresh-cut industry could consider avoiding washing procedures after cutting and implement alternative sanitizing procedures that avoid the partial removal of the wound signal, such as sanitizing only before cutting. © 2020 Society of Chemical Industry.

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The objective of this study was to evaluate the effect of the use of different chemical compounds combined with ultrasound bath on the sanitization of minimally processed carrots. The sanitizers sodium hypochlorite, peracetic acid, and sodium dichloroisocyanurate were investigated, all of them associated with the ultrasound bath, and the aerobic mesophiles and E. coli counts were evaluated. Sodium hypochlorite associated with ultrasound reduced the population of aerobic mesophiles and E. coli by 0.23 and 1.88 log cycles, respectively. For sodium dichloroisocyanurate associated with ultrasound, the reduction was 3.06 and 2.76 log cycles, while for the association with peracetic acid, this reduction was 2.72 and 2.35 log cycles. Thus, the effect of the ultrasound bath and sodium dichloroisocyanurate increased the decontamination efficiency of the minimally processed carrots. In addition, there is analternative to the use of sodium hypochlorite, once they are not involved in reactions with organic compounds and the formation of trihalomethanes, which are harmful to health.(AU)

O objetivo deste estudo foi avaliar o efeito do uso de diferentes compostos químicos combinados ao ultrassom na sanitização de cenouras minimamente processadas. Foram investigados os sanitizantes hipoclorito de sódio, ácido peracético e dicloroisocianurato de sódio, todos associados à técnica de banho de ultrassom, e foram avaliadas as contagens de mesófilos aeróbios e E. coli. O hipoclorito de sódio associado ao ultrassom reduziu em 0,23 e 1,88 ciclos log a população de mesófilos aeróbios e E. coli, respectivamente. Para o dicloroisocianurato de sódio associado ao ultrassom a redução foi de3,06 e 2,76 ciclos log, enquanto que para a associação com o ácido peracético essa redução foi de 2,72e 2,35 ciclos log. Assim, o tratamento composto pela técnica de ultrassom e o dicloroisocianurato de sódio aumentou a eficiência de descontaminação das cenouras minimamente processadas. Além disso, considera-se uma alternativa ao uso do hipoclorito de sódio, uma vez que não estão envolvidos em reações com compostos orgânicos e na formação de trihalometanos, prejudiciais à saúde.(AU)

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RESUMO

The objective of this study was to evaluate the effect of the use of different chemical compounds combined with ultrasound bath on the sanitization of minimally processed carrots. The sanitizers sodium hypochlorite, peracetic acid, and sodium dichloroisocyanurate were investigated, all of them associated with the ultrasound bath, and the aerobic mesophiles and E. coli counts were evaluated. Sodium hypochlorite associated with ultrasound reduced the population of aerobic mesophiles and E. coli by 0.23 and 1.88 log cycles, respectively. For sodium dichloroisocyanurate associated with ultrasound, the reduction was 3.06 and 2.76 log cycles, while for the association with peracetic acid, this reduction was 2.72 and 2.35 log cycles. Thus, the effect of the ultrasound bath and sodium dichloroisocyanurate increased the decontamination efficiency of the minimally processed carrots. In addition, there is analternative to the use of sodium hypochlorite, once they are not involved in reactions with organic compounds and the formation of trihalomethanes, which are harmful to health.

O objetivo deste estudo foi avaliar o efeito do uso de diferentes compostos químicos combinados ao ultrassom na sanitização de cenouras minimamente processadas. Foram investigados os sanitizantes hipoclorito de sódio, ácido peracético e dicloroisocianurato de sódio, todos associados à técnica de banho de ultrassom, e foram avaliadas as contagens de mesófilos aeróbios e E. coli. O hipoclorito de sódio associado ao ultrassom reduziu em 0,23 e 1,88 ciclos log a população de mesófilos aeróbios e E. coli, respectivamente. Para o dicloroisocianurato de sódio associado ao ultrassom a redução foi de3,06 e 2,76 ciclos log, enquanto que para a associação com o ácido peracético essa redução foi de 2,72e 2,35 ciclos log. Assim, o tratamento composto pela técnica de ultrassom e o dicloroisocianurato de sódio aumentou a eficiência de descontaminação das cenouras minimamente processadas. Além disso, considera-se uma alternativa ao uso do hipoclorito de sódio, uma vez que não estão envolvidos em reações com compostos orgânicos e na formação de trihalometanos, prejudiciais à saúde.

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The present study aims to investigate garlic, pepper and coriander plant extract as well as neem and orange peel essential oil effective ness to control Alternaria alternata and Alternaria dauci and their efficiency during carrot seeds germination and emergence. A completely randomized design was used in three different experiments. The first experiment evaluated the effect of plant extracts and essential oils on the incidence of A. alternata and A. dauci . It was done by means of a factorial design applied to five treatments (garlic, pepper, coriander, and neem and orange peel essential oils) at three concentrations (10, 20 and 30%).They also evaluated the controls untreated and with fungicide (Thiram).The second experiment evaluated the effect of the treatment at30% concentration on the germination and emergence of seedlings assessed on trays, and in the third experiment, the presence of A. alternata and A. dauci on the pericarp, endosperm and on the embryo. A. alternata showed higher incidence than A. dauci. The garlic extract and the orange essential oil showed the potential to control A. dauci and A. alternata, because their lower concentrations were able to sufficiently reduce the incidence of these fungi and because they do not affect carrot seeds germination and emergence. A. alternata conidia were found on the embryo (8%), pericarp (17%) and endosperm (31%).(AU)

O presente estudo teve por objetivo verificar a eficiência de extratos vegetais de alho (Allium sativum L.), pimenta dedo-de-moça ( Capsicum baccatum L.), coentro ( Coriandrum sativum L.), óleos essenciais de nim ( Azadirachta indica A. Juss.) e laranja ( Citrus sinensis L. (Osbeck)) no controle de A. alternata e A. dauci , bem como, sobre a germinação e emergência de sementes de cenoura. Foram realizados três experimentos com delineamento experimental inteiramente casualizado. No primeiro experimento, avaliou-se o efeito dos extratos e óleos essenciais vegetais sobre a incidência de A. alternata e A. dauci , em esquema fatorial com cinco tratamentos (alho, pimenta, coentro e óleos essenciais de nim e de laranja), em três concentrações (10, 20 e 30%), acrescido das testemunhas sem tratamento e com fungicida (Thiram). No segundo experimento, avaliou-se o efeito dos tratamentos a 30%, sobre a germinação e emergência de plântulas em bandejas e, no terceiro, a presença de A. alternata e A. dauci no pericarpo, endosperma e embrião. O fungo A. alternata apresentou maior incidência que A. dauci. O extrato de alho e o óleo essencial de laranja demonstraram potencial para o controle de A. alternata e A. dauci , pois, na menor concentração, reduziram satisfatoriamente a incidência desses fungos e foram inócuos a germinação e emergência de sementes de cenoura. Conídios de A. alternata foram identificados no embrião (8%), pericarpo (17%) e endosperma (31%).(AU)

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Carrot (Daucus carota L.) is a vegetable crop that is grown throughout the year across various regions of Brazil in rotation or in succession to other cultures. Herbicide residual effect has emerged as a concern, because of the possibility of carryover. Thus, the objective of this study was to evaluate the effect of tembotrione and atrazine residues - in mixture and isolated - on carrot planted in succession to corn. The experiment was designed in randomized blocks with five replications. Treatments consisted of tembotrione (50.4 g ha(-1)), tembotrione (100.8 g ha(-1)), tembotrione + atrazine (50.4 g ha(-1)+ 2 L ha(-1)), tembotrione + atrazine (100.8 g ha(-1)+ 2 L ha(-1)), and atrazine (2.00 L ha(-1)) applied eight months before carrot seeding, plus a control treatment with no herbicide application. Investigated variables were shoot dry mass, productivity, and classification of carrot roots. The presence of atrazine and tembotrione decreased dry mass in the area, and only tembotrione reduced total root productivity. Thus, there is a carryover effect to tembotrione application that reduces the dry matter accumulation of shoot and total productivity, and an atrazine + tembotrione (100.8 g ha(-1)) mixture reduces the total productivity after application of these herbicides to soil.

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The use of plants to produce chemical compounds with pharmaceutical and nutraceutical applications has intensified in recent years. In this regard, genetic engineering is the most commonly used tool to generate crop lines with enhanced concentrations of desirable chemicals. However, growing genetically modified plants is still limited because they are perceived as potential biological hazards that can create an ecological imbalance. The application of postharvest abiotic stresses on plants induces the accumulation of secondary metabolites and thus can be used as an alternative to genetic modification. The present project evaluated the feasibility of producing shikimic acid (SA) and phenolic compounds (PC) in wounded carrots ( Daucus carota ) treated with glyphosate. The spray application of a concentrated glyphosate solution on wounded carrot tissue increased the concentrations of SA and chlorogenic acid by ∼1735 and ∼5700%, respectively. The results presented herein demonstrate the potential of stressed carrot tissue as a biofactory of SA and PC.

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Turnip (Brassica rapa var. rapa L.), beetroot (Beta vulgaris L.) and carrot (Daucus carota L.) are common vegetables in South Africa. The allelopathic potential of aqueous leaf and root extracts of Aloe ferox Mill.- a highly valued medicinal plant- was evaluated against seed germination and seedling growth of the three vegetables in Petri dish experiments. The extracts were tested at concentrations of 2, 4, 6, 8, and 10 mg/mL. Leaf extract concentrations above 4 mg/mL inhibited the germination of all the crops, while the root extract had no significant effect on germination irrespective of concentration. Interestingly, the lowest concentration of leaf extract stimulated root length elongation of beetroot by 31.71%. Other concentrations significantly inhibited both root and shoot growth of the vegetable crops except the turnip shoot. The most sensitive crop was carrot, with percentage inhibition ranging from 29.15 to 100% for root and shoot lengths. Lower percentage inhibition was observed for the root extract than the leaf extract against shoot growth of beetroot and carrot. The results from this study suggested the presence of allelochemicals mostly in the leaves of A. ferox that could inhibit the growth of the turnip, beetroot and carrot.

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Turnip (Brassica rapa var. rapa L.), beetroot (Beta vulgaris L.) and carrot (Daucus carota L.) are common vegetables in South Africa. The allelopathic potential of aqueous leaf and root extracts of Aloe ferox Mill.- a highly valued medicinal plant- was evaluated against seed germination and seedling growth of the three vegetables in Petri dish experiments. The extracts were tested at concentrations of 2, 4, 6, 8, and 10 mg/mL. Leaf extract concentrations above 4 mg/mL inhibited the germination of all the crops, while the root extract had no significant effect on germination irrespective of concentration. Interestingly, the lowest concentration of leaf extract stimulated root length elongation of beetroot by 31.71%. Other concentrations significantly inhibited both root and shoot growth of the vegetable crops except the turnip shoot. The most sensitive crop was carrot, with percentage inhibition ranging from 29.15 to 100% for root and shoot lengths. Lower percentage inhibition was observed for the root extract than the leaf extract against shoot growth of beetroot and carrot. The results from this study suggested the presence of allelochemicals mostly in the leaves of A. ferox that could inhibit the growth of the turnip, beetroot and carrot.

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Hairy root cultures of Daucus carota L., Ipomoea batatas L. and Solanum aviculare Forst were investigated for their susceptibility to the highly toxic pollutants phenol and chlorophenols and for the involvement of inherent peroxidases in the removal of phenols from liquid media. Roots of D. carota grew normally in medium containing 1000 micromol l(-1) of phenol, whilst normal growth of roots of I. batatas and S. aviculare was only possible at levels up to 500 micromol l(-1). In the presence of chlorophenols, normal root growth was possible only in concentrations not exceeding 50 micromol l(-1), except for I. batatas which was severely affected at all concentrations. Despite the reduction in biomass, the growth of S. aviculare cultures was sustained in medium containing up to 2000 micromol l(-1) of phenol or 2-chlorophenol, and up to 500 micromol l(-1) of 2,6-dichlorophenol. The amounts of phenol removed by the roots within 72 h of treatment were 72.7%, 90.7% and 98.6% of the initial concentration for D. carota, I. batatas and S. aviculare, respectively. For the removal of 2,6-dichlorophenol the values were, respectively, 83.0%, 57.7% and 73.1%. Phenols labelled with 14C were absorbed by the root tissues and condensed with highly polar cellular substances as well as being incorporated into the cell walls or membranes. The results suggest that S. aviculare, an ornamental plant, would be best suited for remediation trials under field conditions.

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Embryogenic callus and suspension cultures of carrot (Daucus carota L., cv. Nantaise), growing on/in medium including 1 mg/l 2,4-dichlorophenoxy acetic acid (2,4-D), were transferred to medium with or without this plant growth regulator, to impair or induce, respectively, further development of somatic embryos. The endogenous hormone levels of the cultures were determined over 7 days by means of radio-immunoassay, to characterize their evolution in the initial stages of embryo development. In general, levels of indoleacetic acid (IAA) and abscisic acid (ABA) showed only short-lived differences among treatments during this time in both types of tissue analyzed (i.e., a peak of IAA in callus cultures in the absence of 2,4-D, 48 h after medium change, and higher ABA contents 144 h after subculture of suspension cultures in the presence of 2,4-D). Gibberellins (1, 3 and 20) were detected only in suspension cultures devoid of 2,4-D, starting 24 h after subculture. Concerning the evaluated cytokinins-zeatin/zeatin riboside and N6(Delta2-isopentenyl) adenine/N6(Delta2-isopentenyl) adenosine-the most remarkable observation is that high levels of the former generally coincided with low concentrations of the latter, indicating a shift from precursor to the active form, and vice versa.

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