Plant Bioactive Compounds in Foods and Food Packages.

There has been growing interest in the use of numerous plant bioactive compounds (PBCs) in food and nutrition technology due to their properties that promote human health by reducing the risk of various serious diseases [...].

The Potential of Essential Oils from Active Packaging to Reduce Ethylene Biosynthesis in Plant Products. Part 1: Vegetables (Broccoli and Tomato).

Essential oils (EOs) extracted from plants have a high potential to reduce ethylene biosynthesis, although their effects have not been deeply studied yet on the key components of the ethylene biosynthesis pathway: l-aminocyclopropane-1-carboxylic (ACC) oxidase activity, ACC synthase activity, and ACC content. Hence, the present study aimed to elucidate the effects of released EOs from active packaging (with different EO doses ranging from 100 to 1000 mg m-2) on the ethylene biosynthesis key components of broccoli and tomato under different storage temperature scenarios. The largest ethylene inhibitory effects on broccoli and tomatoes were demonstrated by grapefruit EO and thyme essential EO (up to 63%), respectively, which were more pronounced at higher temperatures. Regarding EO doses, active packaging with a thyme EO dose of 1000 mg m-2 resulted in the strongest reduction (33-38%) of ethylene production in tomatoes. For broccoli, identical results were shown with a lower grapefruit EO dose of 500 mg m-2. The studied EO-active packaging decreased ACC synthase and ACC oxidase activities by 40-50% at 22 °C. Therefore, this EO-active packaging is a natural and effective technology to reduce ethylene biosynthesis in broccoli and tomatoes when they are stored, even in unsuitable scenarios at high temperatures.

The Potential of Essential Oils from Active Packaging to Reduce Ethylene Biosynthesis in Plant Products. Part 2: Fruits (Blueberries and Blackberries).

Plant essential oils (EOs) have an important ability to inhibit ethylene biosynthesis. Nevertheless, the effects of EOs on the key components of ethylene biosynthesis (l-aminocyclopropane-1-carboxylic (ACC) oxidase activity, ACC synthase activity, and ACC content) have not yet been thoroughly studied. Accordingly, this study focused on the effects of emitted EOs from active packaging (EO doses from 100 to 1000 mg m-2) on the key components of ethylene biosynthesis of blueberries and blackberries under several storage temperatures. Anise EO and lemon EO active packaging induced the greatest inhibitory effects (60-76%) on the ethylene production of blueberries and blackberries, respectively, even at high storage temperatures (22 °C). In terms of EO doses, active packaging with 1000 mg m-2 of anise EO or lemon EO led to the highest reduction of ethylene production, respectively. At 22 °C, the investigated EO active packing reduced the activities of ACC synthase and ACC oxidase up to 50%. In order to minimise ethylene biosynthesis in blueberries and blackberries when they are stored even under improper temperature scenarios at high temperatures, this EO active packaging is a natural and efficient technological solution.

Applications of Plant Bioactive Compounds as Replacers of Synthetic Additives in the Food Industry.

According to the Codex Alimentarius, a food additive is any substance that is incorporated into a food solely for technological or organoleptic purposes during the production of that food. Food additives can be of synthetic or natural origin. Several scientific evidence (in vitro studies and epidemiological studies like the controversial Southampton study published in 2007) have pointed out that several synthetic additives may lead to health issues for consumers. In that sense, the actual consumer searches for "Clean Label" foods with ingredient lists clean of coded additives, which are rejected by the actual consumer, highlighting the need to distinguish synthetic and natural codded additives from the ingredient lists. However, this natural approach must focus on an integrated vision of the replacement of chemical substances from the food ingredients, food contact materials (packaging), and their application on the final product. Hence, natural plant alternatives are hereby presented, analyzing their potential success in replacing common synthetic emulsifiers, colorants, flavorings, inhibitors of quality-degrading enzymes, antimicrobials, and antioxidants. In addition, the need for a complete absence of chemical additive migration to the food is approached through the use of plant-origin bioactive compounds (e.g., plant essential oils) incorporated in active packaging.

Phytochemical Fortification in Fruit and Vegetable Beverages with Green Technologies.

BACKGROUND: Phytochemical, bioactive and nutraceutical compounds are terms usually found in the scientific literature related to natural compounds found in plants linked to health-promoting properties. Fruit and vegetable beverages (mainly juice and smoothies) are a convenient strategy to enhance the consumption of horticultural commodities, with the possibility of being fortified with plant byproducts to enhance the content of bioactive compounds. OBJECTIVE: This review aims to analyse the different green technologies applied in beverage processing with a fortification effect on their health promoting compounds. RESULTS: Fortification can be performed by several strategies, including physical elicitors (e.g., processing technologies), plant/algae extract supplementation, and fermentation with probiotics, among others. Thermal processing technologies are conventionally used to ensure the preservation of food safety with a long shelf life, but this frequently reduces nutritional and sensory quality. However, green non-thermal technologies (e.g., UV, high-pressure processing, pulsed electric fields, ultrasounds, cold plasma, etc.) are being widely investigated in order to reduce costs and make possible more sustainable production processes without affecting the nutritional and sensory quality of beverages. CONCLUSIONS: Such green processing technologies may enhance the content of phytochemical compounds through improvement of their extraction/bioaccessibility and/or different biosynthetic reactions that occurred during processing.

Synergistic Antimicrobial Activities of Combinations of Vanillin and Essential Oils of Cinnamon Bark, Cinnamon Leaves, and Cloves.

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402-404 against L. monocytogenes and 778-721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.

Packaging of Fresh Sliced Mushrooms with Essential Oils Vapours: A New Technology for Maintaining Quality and Extending Shelf Life.

The use of vapour of essential oils (EOs) through an innovative pilot-plant packaging device was studied to preserve the quality of sliced mushrooms during storage. A mix of EOs (eugenol, bergamot EO, and grapefruit EO) was vaporized (100 and 125 µL L-1) and applied during packaging of sliced mushrooms under modified atmosphere packaging (MAP); then, the product quality was studied during cold storage up to 12 days. The highest colour changes of EOs125 samples, which were observed in the mushroom stipe, were not observed with the EOs100 atmosphere. Thus, the high polyphenoloxidase activity observed in untreated samples after 5-7 days was highly controlled with the vapour EOs atmospheres. Furthermore, the visual appearance scores of EOs100 samples were still over the limit of usability, while untreated samples were already below this threshold after 5 days of storage. A strong bacteriostatic effect was achieved with vapour EOs, reducing the Pseudomonas spp. (the main microbial genus in cultivated mushrooms) growth by ≈1.7 log CFU g-1, regardless of the EOs dose, after 12 days. The activity of phenyl ammonia lyase was also reduced up to ≈0.4 enzymatic units with the EOs100 treatment. Conclusively, packaging of sliced mushrooms under an atmosphere enriched with 100 µL L-1 EOs vapour highly controlled the quality loss of sliced mushrooms owing to their enzymatic inhibition and high bacteriostatic effect.

Antioxidant and Antimicrobial Effect of Plant Essential Oils and Sambucus nigra Extract in Salmon Burgers.

The antioxidant capacity of oregano (OEO) and clove (CLEO) essential oils and black elderberry (Sambucus nigra) flower extract (SNE) were compared with butylhydroxytoluene (BHT) regarding its protection against lipid peroxidation and microbial counts in salmon burgers stored at 4 °C for 14 days and after cooking. The content of total phenols was 5.74% in OEO, 2.64% in CLEO and 2.67 % in the SNE. The total phenolic content and the antioxidant capacity were significantly higher (p < 0.05) for SNE and OEO. Both essential oils showed a similar IC50 and inhibition percentage of lipid peroxidation to BHT. The combination of OEO and SNE reduced 29% of thiobarbituric acid reactive substances (TBARS), while BHT reduced 31% of TBARS generated during refrigeration storage in salmon burgers in relation to the control sample without antioxidants. Additionally, the microbial counts after 14 days of refrigeration were the lowest in burgers when the combination of OEO and SNE was used. This study concludes that OEO and SNE can be used as inhibitors of lipid oxidation in salmon products and as natural candidates to replace commonly used synthetic antioxidants and antimicrobials in these food products.

The Application of Essential Oil Vapors at the End of Vacuum Cooling of Fresh Culinary Herbs Promotes Aromatic Recovery.

Aroma is an important quality parameter of fresh culinary herbs that may be highly affected after postharvest treatments. The innovative technology of vapor essential oil (EO) application under vacuum conditions may recover aroma lost during the postharvest processing of plant products like aromatic herbs. Hence, this study assessed the aroma recovery effect of vapor EOs applied during vacuum cooling on curly parsley and dill. The volatile organic compounds (VOCs) profiles of these aromatic herbs were studied by static headspace solid-phase microextraction (SPME), and the VOCs sorption kinetics onto the SPME stir-bar coating were modeled by the Baranyi model. At the pilot plant scale, the total VOCs contents of parsley and dill (whose extractability was increased by 10-20% after a single vacuum process) were enhanced by 4.5- and 2-fold, respectively, when vapor EOs were applied. In particular, 1,3,8-p-menthatriene and carvone (parsley) increased by 18.7- and 7.3-fold, respectively, while dill ether (the characteristic VOC of dill) augmented by 2.4-fold after vapor EOs were applied under vacuum conditions. The aroma recovery of culinary herbs was successfully validated at an industrial level in an installation developed by our group to apply vapor EOs within a vacuum cooling system, reaching total VOC recoveries of 4.9- and 2.3-fold in parsley and dill, respectively.

Revalorized broccoli by-products and mustard improved quality during shelf life of a kale pesto sauce.

The effect of revalorized Bimi leaves (B) and/or mustard (M) addition, as supplementary ingredients, to develop an innovative kale (K) pesto sauce was studied. Microbial, physicochemical (color, total soluble solids content -SSC-, pH and titratable acidity -TA-) and sensory quality were studied during 20 days at 5 °C. Bioactive compounds changes (total phenolics, total antioxidant capacity and glucoraphanin contents) were also monitored throughout storage. The high TA and pH changes in the last 6 days of storage were avoided in the K+B pesto when adding mustard, due to the antimicrobial properties of this brassica seed. SSC was increased when B + M were added to the K pesto, which positively masked the kale-typical bitterness. Mustard addition hardly change yellowness of the K pesto, being not detected in the sensory analyses, showing K+B+M pesto the lowest color differences after 20 days of shelf life. The addition of Bimi leaves to the K pesto enhanced its phenolic content while mustard addition did not negatively affect such total antioxidant compounds content. Finally, mustard addition effectively aimed to glucoraphanin conversion to its bioactive products. Conclusively, an innovative kale pesto supplemented with Bimi by-products was hereby developed, being its overall quality well preserved up to 20 days at 5 °C due to the mustard addition.

Active Cardboard Packaging With Encapsulated Essential Oils for Enhancing the Shelf Life of Fruit and Vegetables.

The quality loss of fruit and vegetables should be minimized to reduce food waste during retail. In that sense, sustainable and effective post-harvest techniques/technologies are needed, showing active packaging including encapsulated essential oils a high potential. In that sense, we studied the effect of different sized active packages (including ß-cyclodextrin-EOs inclusion complex) on the quality of grapes, nectarines, and lettuces (as models of berry fruit, stone fruit, and leafy vegetables) during storage at 2°C (90-95% relative humidity). The active industrial tray showed the best effect on grapes and lettuce quality, as it reduced rachis dehydration and product weight loss (reduced by ≈50% in grapes after 30 days), reduced berry shatter (reduced by ≈40% in grapes after 30 days), highly maintained the physicochemical quality (soluble solid content, titratable acidity and firmness), and also reduced microbial growth (0.5-1.4 lower log units than non-active industrial tray). For nectarines, the package with the biggest active surface (large tray, 200 × 300 × 90) also showed the best-quality retention compared to smaller packages, showing nectarines within active large tray better microbial quality (0.6-1 lower log units than non-active large tray) and firmness. As expected, flow packaging of nectarines (using active trays) better controlled the product weight loss. In conclusion, active cardboard packages with greater active surface better preserved quality of grapes, nectarines and lettuce, which sensory quality was accepted after more than 30, 25, and 14 days at 2°C, respectively, contrary to non-active samples (~1 week less).

Active Paper Sheets Including Nanoencapsulated Essential Oils: A Green Packaging Technique to Control Ethylene Production and Maintain Quality in Fresh Horticultural Products-A Case Study on Flat Peaches.

Plant essential oils (EOs) have several bioactive properties, highlighting their high antimicrobial and antioxidant capacities. As such, the use of EOs in active packaging has received special attention in the last few years. Nevertheless, the inhibitory effect of EOs on quality-degrading enzymatic systems of plant products during postharvest life has not been deeply studied. The effects of an EO active paper sheet on ethylene biosynthesis and quality (and related quality-degrading enzymes) of flat peach (Prunus persica var. platycarpa) samples were studied during 5 days (continental terrestrial transport) or 26 days (long maritime transport) storage at 2 or 8 °C, both followed by commercialization simulations (4 days at 22 °C). EOs released from active packaging reduced ethylene production by 40-50%, and by up to 70% after commercialization periods. These results were correlated with lower 1-aminocyclopropanecarboxylic acid (ACC) content and ACC-oxidase activity. Physicochemical fruit quality (as indicated by soluble solids content, titratable acidity, color, and firmness) was also better preserved by EO active sheets due to enzymatic inhibition (polygalacturonase and polyphenoloxidase). Furthermore, phenolic compounds (mainly catechin and cyanidin-3 glucoside) and total antioxidant capacity were increased (by up to 30 and 70%, respectively) in EO-packaged samples after 8 °C storage and the subsequent commercialization period. Conclusively, EO active paper sheets controlled ethylene production in flat peaches, maintained fruit quality, and even increased health-promoting bioactive compounds.

A new advanced packaging system for extending the shelf life of refrigerated farmed fish fillets.

BACKGROUND: An innovative pilot-plant packaging was developed and evaluated for applying oregano essential oil (OEO) vapours in conditions of high vacuum for exploring the antimicrobial effect of essential oil vapours applied immediately before packaging of fish fillets. Farmed sea bream (Sparus aurata) fresh fillets have been used as a model for validating this new technology. These fillets, as a refrigerated product under modified atmosphere packaging (MAP), have a relatively short shelf life (12-14 days) mainly due to the fast microbial growth. The effects of conventional OEO dippings [pretreatment dipping (0.1% of OEO) of whole fish (T1) and filleted sea bream (T2)] were compared with the OEO application in vapour phase (67 µL L-1 ) under vacuum (5-10 hPa) immediately before MAP fillet packaging (T3). RESULTS: T3/T2 samples showed the lowest microbial growth after 28 days at 4 °C, with loads up to 1/2.6 log units for Enterobacteria/lactic acid bacteria compared to untreated samples. The initial trimethylamine nitrogen (TMA-N) content (2.6 mg kg-1 ) increased in T1 and T2/T3 samples by 9.6 and 6/7 units, respectively, after 28 days. Quality Index Method (QIM) better reflected the fish fillets shelf life than texture and colour measurements. The shelf life of T3/T2 samples was established in at least 28 days (4 °C), while the QIM threshold (6) was exceeded after 7/21 days in untreated/T1 fillets. CONCLUSION: The fish shelf life was extended with vapour OEO treatment using this new technology, similarly to OEO dipping treatment, according to QIM, corroborated by the microbial quality and TMA-N contents. © 2020 Society of Chemical Industry.

Active Cardboard Box with Smart Internal Lining Based on Encapsulated Essential Oils for Enhancing the Shelf Life of Fresh Mandarins.

Mandarins are usually sold in bulk and refrigerated in open cardboard boxes with a relatively short shelf-life (12-15 days) due to physiological and pathological disorders (rot, dehydration, internal breakdown, etc.). The influence of a controlled release of essential oils (EOs) from an active packaging (including ß-cyclodextrin-EOs inclusion complex) was studied on the mandarin quality stability, comparing different sized cardboard trays and boxes, either non-active or active, at the pilot plant scale (experiment 1; commercialization simulation at room temperature after a previous simulation of short transportation/storage of 5 days at 8 °C). Then, the selected package was further validated at the industrial scale (experiment 2; cold storage at 8 °C up to 21 days). Among package types, the active large box (≈10 kg fruit per box) better maintained the mandarin quality, extending the shelf life from two weeks (non-active large box) to three weeks at room temperature. Particularly, the active large box highly controlled microbial growth (up to two log units), reduced weight losses (by 1.6-fold), reduced acidity, and increased soluble solids (highly appreciated in sensory analyses), while it minimized colour and controlled firmness changes after three weeks. Such trends were also observed during the validation experiment, extending the shelf life (based on sensory quality) from 14 to at least 21 days. In conclusion, the mandarin's shelf life with this active cardboard box format was extended more than one week at 8 °C.

UV-C pretreatment of fresh-cut faba beans (Vicia faba) for shelf life extension: Effects of domestic microwaving for consumption.

Faba beans have a short shelf life which is even reduced after fresh-cut processing mainly due to browning and dehydration. In that sense, the effects of a UV-C treatment (3 kJ m-2), compared with non-exposed beans (CTRL), were studied on the sensory and microbial quality, and bioactive and anti-nutritional content of fresh-cut faba beans (cv. Muchamiel) during storage at 5 ℃. The effect of a domestic microwaving (3 min, 900 W) on bioactive and anti-nutritional compounds of fresh seeds prior to consumption at each sampling time was also studied. UV-C treatment extended the fresh-cut faba bean shelf life from 7 to 10 days with browning score (the main sensory parameter adversely affected) of 8 and 1 log unit lower than CTRL at day 10. UV-C did not negatively affect the total antioxidant capacity of samples during storage. The phytic acid and raffinose contents decreased by 30/40%, respectively, after 10 days, without influence of the UV-C treatment. Microwaving reduced the phytic acid and condensed tannins contents by 30% in those samples stored for up to six days, with low microwaving effect in the last storage days. Nevertheless, UV-C improved the condensed tannins reductions through storage (≈30%) compared with non-irradiated samples.

Microwave heating modelling of a green smoothie: Effects on glucoraphanin, sulforaphane and S-methyl cysteine sulfoxide changes during storage.

BACKGROUND: The heating of a green smoothie during an innovative semi-continuous microwave treatment (MW; 9 kW for 15 s) was modelled. Thermal and dielectric properties of the samples were previously determined. Furthermore, the heating effect on the main chemopreventive compounds of the smoothie and during its subsequent storage up to 30 days at 5 or 15 °C were studied. Such results were compared to conventional pasteurisation (CP; 90 °C for 45 s) while unheated fresh blended samples were used as the control. RESULTS: A procedure was developed to predict the temperature distribution in samples inside the MW oven with the help of numerical tools. MW-treated samples showed the highest sulforaphane formation after 20 days, regardless of the storage temperature, while its content was two-fold reduced in CP samples. Storage of the smoothie at 5 °C is crucial for maximising the levels of the bioactive compound S-methyl cysteine sulfoxide. CONCLUSION: The proposed MW treatment can be used by the food industry to obtain an excellent homogeneous heating of a green smoothie product retaining high levels of bioactive compounds during subsequent retail/domestic storage up to 1 month at 5 °C. © 2017 Society of Chemical Industry.

Natural vitamin B12 and fucose supplementation of green smoothies with edible algae and related quality changes during their shelf life.

BACKGROUND: Some algae are an excellent sources of vitamin B12, of special interest for vegetarian/vegan consumers, and of fucose to supplement fruit and vegetable beverages such as smoothies. Nevertheless, supplementation of smoothies with algae may lead to possible quality changes during smoothie shelf life that need to be studied. Therefore, the quality changes in fresh green smoothies supplemented (2.2%) with nine edible algae (sea lettuce, kombu, wakame, thongweed, dulse, Irish moss, nori, Spirulina and Chlorella) were studied throughout 24 days at 5 °C. RESULTS: The initial vitamin C content - 238.7-326.0 mg kg-1 fresh weight (FW) - of a 200 g portion of any of the smoothies ensured full coverage of its recommended daily intake, and still supplying 50-60% of the recommended intake after 7 days. Chlorella and Spirulina smoothies showed the highest vitamin B12 content (33.3 and 15.3 µg kg-1 FW, respectively), while brown algae showed fucose content of 141.1-571.3 mg kg-1 FW. These vitamin B12 and fucose contents were highly maintained during shelf life. CONCLUSION: The Spirulina supplementation of a 200 g smoothie portion ensured full coverage of the recommended vitamin B12 intake, with lower vitamin C degradation, during a shelf life of 17 days. Furthermore, thongweed and kombu are also considered as excellent fucose sources with similar shelf life. © 2017 Society of Chemical Industry.

Improved quality of a vitamin B12-fortified 'ready to blend' fresh-cut mix salad with chitosan.

A vitamin B12-fortified (0.25 mg L-1) chitosan (10 g L-1) coating was applied to a ready-to-blend fresh-cut salad including melon, pineapple and carrot, which was stored at 5 ℃ up to nine days. Uncoated samples were used as control while the vitamin B12 effect was compared to non-fortified chitosan-coated samples. Beverages were prepared on blending days 0, 4, 7 and 9 with subsequent storage at 5 ℃ for 0, 24 and 48 h. Physicochemical quality of fresh blended beverages was well preserved throughout storage. The chitosan coating highly reduced epiphytic microflora growth and polyphenoloxidase/peroxidase activities. No relevant variations of total phenolic contents were observed between different fresh blended beverages. However, its total antioxidant capacity reported after blending was lower as storage time of ready-to-blend samples increased. Fortified samples showed a vitamin B12 content of 8.6 µg kg-1 on processing day, ensuring 200 mL of such beverage the recommended daily intake of this vitamin. In conclusion, a ready-to-blend fruit/vegetable mix, fortified with vitamin B12, was developed with a shelf life of nine days at 5 ℃ showing the prepared beverages good quality during subsequent storage for 48 h at 5 ℃.

Preservation of bioactive compounds of a green vegetable smoothie using short time-high temperature mild thermal treatment.

Smoothies represent an excellent and convenient alternative to promote the daily consumption of fruit and vegetables in order to obtain their health-promoting benefits. Accordingly, a green fresh vegetables smoothie (77.2% cucumber, 12% broccoli and 6% spinach) rich in health-promoting compounds was developed. Soluble solids content, pH and titratable acidity of the smoothie were 4.3 ± 0.4°Bx, 4.49 ± 0.01 and 0.22 ± 0.02 mg citric acid 100-1 g fw, respectively. Two thermal treatments to reduce microbial loads and preserve quality were assayed: T1 (3 min at 80 ℃) and T2 (45 s at 90 ℃). Fresh blended unheated samples were used as control (CTRL). The smoothie presented a viscoelastic behaviour. T1 and T2 treatments reduced initial microbial loads by 1.3-2.4 and 1.4-3.1 log units, respectively. Samples were stored in darkness at 5 and 15 ℃. Colour and physicochemical changes were reduced in thermal-treated samples throughout storage, which were better preserved at 5 ℃ rather than at 15 ℃. Vitamin C changes during storage were fitted with a Weibullian distribution. Total vitamin C losses of T1 and T2 samples during storage at 15 ℃ were greatly reduced when they were stored at 5 ℃. Initial total phenolic content (151.1 ± 4.04 mg kg-1 fw) was 44 and 36% increased after T1 and T2 treatments, respectively. The 3-p-coumaroyl quinic and chlorogenic acids accounted the 84.7 and 7.1% relative abundance, respectively. Total antioxidant capacity (234.2 ± 20.3 mg Trolox equivalent kg-1 fw) remained constant after the thermal treatments and was better maintained during storage in thermal-treated samples. Glucobrassicin accounted the 81% of the initial total glucosinolates content (117.8 ± 22.2 mg kg-1 fw) of the smoothie. No glucosinolates losses were observed after T2 treatment being better preserved in thermal-treated samples. Conclusively, a short time-high temperature mild thermal treatment (T2) showed better quality and bioactive compounds retention in a green fresh vegetable smoothie during low temperature storage.

UV-C and hyperoxia abiotic stresses to improve healthiness of carrots: study of combined effects.

Phenolic compounds are phytochemicals with high health-promoting properties. Carrot is a vegetable highly worldwide consumed although its phenolic content is low compared to other plant products. The aim of this work was to evaluate changes in phenolic compounds in carrots caused by abiotic stresses. The phenylalanine ammonia-lyase (PAL) activity, phenolic compounds and total antioxidant capacity (TAC) changes during storage up to 72 h at 15 °C after wounding (shredding), 9 kJ UV-C m-2 pretreatment and hyperoxia (80 kPa) conditions of carrots were studied. Shredding and hyperoxia storage induced the highest phenolic compounds and TAC enhancements. Accumulation of phenolic compounds in shredded carrots could be structured in the following phases: 1st phase (<24 h): unchanged phenolic compounds levels with minimum PAL activity; 2nd phase (24-48 h): moderate phenolic increases (≈600-700 mg CAE kg-1 accumulated in 24 h) concurring with the greatest increase of PAL activity; 3nd phase (48-72 h): high phenolic increases (≈1600-2700 mg CAE kg-1, accumulated in 24 h) while a moderate increment of PAL activity was registered. Although UV-C pretreatment of shreds reduced phenolic accumulation, 600 % increments were still registered in those samples stored under hyperoxia conditions for 72 h. However, the contents of chlorogenic acid at 72 h were 1.4-fold higher in irradiated shreds under hyperoxia compared to the same samples under air conditions.