Health-Promoting Properties of Processed Red Cabbage (Brassica oleracea var. capitata f. rubra): Effects of Drying Methods on Bio-Compound Retention.

The aim of this work is to describe the effect of convective drying (CD), vacuum drying (VD), infrared drying (IRD), low-temperature vacuum drying (LTVD) and freeze drying (FD) on bio-compound retention of red cabbage and its beneficial health properties. The total phenolics content (TPC), flavonoids (TFC), anthocyanin (TAC) and glucosinolates (TGC) were determined by spectrophotometry. The profiles of phenolic acids, amino acids and fatty acids were determined by HPLC-UV-DAD, LC-DAD and GC-FID, respectively. Antioxidant potential was verified by DPPH and ORAC assays. The antiproliferative activity was measured in the human gastric cell line (AGS). Anti-inflammatory activity was evaluated by phorbol 12-myristate 13-acetate and arachidonic acid models. VD showed high values of TPC = 11.89 ± 0.28 mg GAE/g d.m.; TFC = 11.30 ± 0.9 mg QE/g d.m.; TAC = 0.265 ± 0.01 mg Cya3glu/g d.m.; and TGC = 51.15 ± 3.31 µmol SE/g d.m. Caffeic acid, ferulic acid and sinapic acid were identified. The predominant amino acid and fatty acid were glutamic acid and γ-linolenic acid, respectively. The antioxidant potential was dependent on drying methods for both DPPH and ORAC assays. Dried red cabbage extracts showed clear anti-inflammatory and antiproliferative activity. The dehydration process is an alternative for the retention of bio-compounds and health-promoting properties of red cabbage.

Low-Temperature Vacuum Drying on Broccoli: Enhanced Anti-Inflammatory and Anti-Proliferative Properties Regarding Other Drying Methods.

Low-temperature vacuum drying (LTVD) has shown great potential for drying vegetables. It could avoid excessive degradations of active compounds with potential therapeutic agents. In this study, the effect on several relevant bioactive compounds, anti-inflammatory activity, and anti-proliferative activity of broccoli (Brassica oleracea var. italica) were evaluated. Effects of other drying methods, including vacuum drying (VD), convective drying (CD), infrared drying (IRD), and freeze drying (FD), were also comparatively evaluated. The results of all dried samples showed high polyunsaturated fatty acid contents (of up to 71.3%) and essential amino acid contents (of up to 8.63%). The LTVD method stands out above the other drying methods, since it obtained the highest content of total phenols, chlorogenic acid, and ferulic acid. Both the LTVD and CD samples demonstrated high anti-inflammatory and anti-proliferative activities. These CD and LTVD samples were also the most active against the breast carcinoma MDA-MB-23 cell line. Due to the good retention of bioactive compounds via LTVD, the obtained dried broccoli here can be used in a near time as an ingredient for the development of novel natural products with anti-inflammatory and anti-proliferative effects.

Assessment of Bio-Compounds Content, Antioxidant Activity, and Neuroprotective Effect of Red Cabbage (Brassica oleracea var. Capitata rubra) Processed by Convective Drying at Different Temperatures.

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and no efficient therapy able to cure or slow down PD is available. In this study, dehydrated red cabbage was evaluated as a novel source of bio-compounds with neuroprotective capacity. Convective drying was carried out at different temperatures. Total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and glucosinolates (TGC) were determined using spectrophotometry, amino acid profile by LC-DAD and fatty acid profile by GC-FID. Phenolic characterization was determined by liquid chromatography-high-resolution mass spectrometry. Cytotoxicity and neuroprotection assays were evaluated in SH-SY5Y human cells, observing the effect on preformed fibrils of α-synuclein. Drying kinetic confirmed a shorter processing time with temperature increase. A high concentration of bio-compounds was observed, especially at 90 °C, with TPC = 1544.04 ± 11.4 mg GAE/100 g, TFC = 690.87 ± 4.0 mg QE/100 g and TGC = 5244.9 ± 260.2 µmol SngE/100 g. TAC degraded with temperature. Glutamic acid and arginine were predominant. Fatty acid profiles were relatively stable and were found to be mostly C18:3n3. The neochlorogenic acid was predominant. The extracts had no cytotoxicity and showed a neuroprotective effect at 24 h testing, which can extend in some cases to 48 h. The present findings underpin the use of red cabbage as a functional food ingredient.

Combined Effect of High Hydrostatic Pressure and Proteolytic Fraction P1G10 from Vasconcellea cundinamarcensis Latex against Botrytis cinerea in Grape Juice.

The effect of high hydrostatic pressure (HHP) and the proteolytic fraction P1G10 from papaya latex was studied to find out whether a synergy exists in the growth inhibition of Botrytis cinerea in grape juice, contributing to the improvement of conservation techniques and extending the shelf life and quality of food products. Grape juice (GJ) diluted to 16 °Brix with a water activity (aw) of 0.980 was prepared from a concentrated GJ and used in this study. Results indicated a 92% growth inhibition of B. cinerea when exposed to 1 mg/mL of P1G10 and 250 MPa/4 min of pressure treatment. The proximate composition and antioxidant compounds present in the GJ were not significantly affected after the treatments. Eight phenolic compounds and two flavonoids in GJ were identified and quantified, with values fluctuating between 12.77 ± 0.51 and 240.40 ± 20.9 mg/L in the control sample (0.1 MPa). The phenolic compounds showed a significant decrease after the applied treatments, with the HHP sample having a content of 65.4 ± 6.9 mg GAE/100 mL GJ. In conclusion, a synergistic effect at moderate HHP of 250 MPa/4 min with the addition of P1G10 was observed, and the successful development of a stable and acceptable GJ product was possible.

Evaluation of the antioxidant, anti-inflammatory, and anti-tumoral properties of bioactive compounds extracted from murta berries (Ugni molinae T.) dried by different methods.

This study evaluated the effects of different drying methods (freeze drying, vacuum drying, infrared drying, convective drying, and sun drying) on the biological properties of berries from the Chilean murta (Ugni molinae Turcz) shrub. Physical-chemical properties (proximal composition, dietary fiber, sugars) were determined. Total phenolic content through the method of Folin-Ciocalteau, the profile of phenol compounds was determined by HPLC, and antioxidant potential by DPPH and ORAC assays were also evaluated. The topic anti-inflammatory effect was evaluated by mice´s ear edema, and in vitro anti-tumoral activity was tested by MTT assay. The chemical properties of dried berries differed significantly based on the drying method: freeze-dried murta berries showed increased total phenolic content extracted over fresh and dried samples. In addition, this lyophilized extract stood out in its antioxidant potential, in both assays evaluated (DPPH and ORAC), compared to the other drying methods. Notwithstanding, vacuum- and infrared-dried murta also showed a higher ORAC value. Antioxidant potential was significantly associated with phenolic compounds catechin and pyrogallol, which were the most abundant phenolic compounds present in all samples. The anti-inflammatory activity was most effective under freeze-drying and vacuumdrying conditions. Moreover, vacuum drying and infrared drying best preserved the anti-tumoral effect on cancer cells.

Comprehensive Evaluation of the Bioactive Composition and Neuroprotective and Antimicrobial Properties of Vacuum-Dried Broccoli (Brassica oleracea var. italica) Powder and Its Antioxidants.

In this study, vacuum drying (VD) was employed as an approach to protect the bioactive components of and produce dried broccoli powders with a high biological activity. To achieve these goals, the effects of temperature (at the five levels of 50, 60, 70, 80 and 90 °C) and constant vacuum pressure (10 kPa) were evaluated. The results show that, with the increasing temperature, the drying time decreased. Based on the statistical tests, the Brunauer-Emmett-Teller (BET) model was found to fit well to sorption isotherms, whereas the Midilli and Kucuk model fit well to the drying kinetics. VD has a significant impact on several proximate composition values. As compared with the fresh sample, VD significantly reduced the total phenol, flavonoid and glucosinolate contents. However, it was shown that VD at higher temperatures (80 and 90 °C) contributed to a better antioxidant potential of broccoli powder. In contrast, 50 °C led to a better antimicrobial and neuroprotective effects, presumably due to the formation of isothiocyanate (ITC). Overall, this study demonstrates that VD is a promising technique for the development of extracts from broccoli powders that could be used as natural preservatives or as a neuroprotective agent.

Drying Kinetic Modeling and Assessment of Mineral Content, Antimicrobial Activity, and Potential α-Glucosidase Activity Inhibition of a Green Seaweed (Ulva spp.) Subjected to Different Drying Methods.

The green algal genus Ulva grows widely on all continents and is used for several applications such as functional foods, cosmeceuticals, nutraceuticals, and pharmaceuticals due to its nutritional characteristics. However, to increase its shelf-life and retain its bioactive components, it is necessary to apply some conservation technology, such as drying. The aim of this work is to describe the drying kinetic behavior of the green seaweed Ulva spp. by applying three dehydration methods: convective drying (CD), vacuum drying (VD), and solar drying (SD) by mathematical modeling and determining the retention of mineral content by atomic absorption spectroscopy and the antimicrobial potential against four strains such as Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae, and Penicillium sp. by measurement of inhibition zones and α-glucosidase activity inhibition, as reported by IC50 determination. A freeze-dried sample was used as the control. The equilibrium moisture values calculated using the Guggenheim-Anderson-de Boer model were 0.0108, 0.0108, and 0.0290 g water/g d.m., for CD, VD and SD, respectively. The Midilli and Kucuk model showed robustness to fit all the experimental data of drying kinetic modeling. Ulva spp. is an important source of potassium with a ratio of Na/K < 0.29. Inhibition halos were observed in all samples against S. cerevisiae and Penicillium sp. with higher values than fluconazole action. An inhibitory effect on α-glucosidase activity was observed in all samples, mainly in the freeze-dried sample. Finally, dried Ulva spp. is a rich source of macro- and microminerals with antimicrobial activity and is a potential α-glucosidase inhibitor. Thus, it can be considered as a potential functional ingredient for food manufacturing.

Dietary fibre in processed murta (Ugni molinae Turcz) berries: bioactive components and antioxidant capacity.

In this study the dietary fibre (DF) of fresh and processed murta berries was characterised with respect to bioactive and antioxidant properties. DF content was determined by three different methods (AOAC, dialysis membrane and indigestible fraction methods) comparing their effectiveness. The antioxidant activity of phenolic compounds (PC) in purée, fruit leather and isolated DF of murta berries was evaluated by DPPH and ORAC assays. Total phenolics and flavonoids linked to DF were determined by colorimetric tests, while PC profiles in the respective murta products were identified by HPLC. DF concentration was > 50 g/100 g dm, fluctuating between 52.03 ± 1.32 and 57.18 ± 0.61 g/100 g dm, exhibiting simultaneously high antioxidant activity, with ORAC values of 38,190 ± 661 and 26,425 ± 1399 µmol Trolox equivalent/100 g dm in the isolated DF of fresh murta berries and processed murta fruit leather respectively, which enabled a classification as antioxidant dietary fibre. Total phenolics and flavonoids linked to DF retained a high concentration in the fruit leather, implying a favourable effect of processing. Gallic acid and pyrogallol were found associated to DF, at a level of 34.03 ± 1.17 and 631.07 ± 22.10 mg/100 g dm in the fresh berries respectively, which conferred to murta berries a functional property not yet reported. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05416-1.

Importance of crop phenological stages for the efficient use of PGPR inoculants.

During the last decades, the incorporation of beneficial microorganisms in agriculture crop management has become a common practice. Seed coating of these microorganisms still faces technical issues, which limit its implementation in conventional agriculture. An adaption to widely established agricultural practices, e.g. fertigation, could help to overcome these issues. Here, using Bacillus velezensis strain BBC047, we show the influence of the crop phenological stages on the efficiency and success of microbial inoculation under agricultural conditions. In the commercial nursery, strain BBC047 improved growth in a variety of horticulture crops like basil, cabbage, tomato and bell pepper, the latter with the strongest effects in strengthening and accelerating the seedling growth (root and aerial biomass). For a field trial under productive conditions, different application strategies were compared, using bell pepper (Capsicum annuum L.) as crop under fertigation: conventional management (T1), application to the seedling (only nursery, T2), only post-transplant application (field, T3) and a combination of both (T4). In T2 and T4, the post-transplantation survival rate (p < 0.05) improved and the productivity of the plants increased (> 100%). Applications of BBC047 post-transplantation (T3) caused a lower increase in productivity (25%). Fruits from all three application strategies contained significantly more Vitamin C. We conclude that in conventional agriculture, the applications of PGPR inoculants to early crop phenological stages like nurseries are a viable alternative for the efficient use of PGPR inoculants. In comparison, a late introduction of a PGPR reduces its beneficial effect on crop productivity. We highlight that an appropriate timing in the use of PGPR inoculants is crucial for product development and success in sustainable agriculture.

Vacuum drying of Chilean papaya (Vasconcellea pubescens) fruit pulp: effect of drying temperature on kinetics and quality parameters.

Chilean papaya is grown in Central Chile and is considered to be an important source of fiber, sugars, and antioxidants. The effect of different vacuum drying temperatures (40, 50, 60, 70, and 80 °C) on the composition of papaya pulp was evaluated. The inhibitory effect of papaya extracts on α-glucosidase activity, as a regulator of blood sugar, was also evaluated. Drying reduced water activity of the pulp to less than 0.6, thereby, assuring the product stability, while maintaining simple sugars, vitamin C, and total flavonoids. Total phenolic content and antioxidant capacity by DPPH assay increased with respect to the fresh pulp by 1.5 and 2.6 times, respectively. The inhibitory effect of papaya extracts on α-glucosidase was evaluated by determining the IC50 for each sample and the acarbose equivalents. The results indicate the suitability of the dried extract of Chilean papaya as a regulator of glucose metabolism in Type II diabetes patients.

Effects of drying methods on the characterization of fatty acids, bioactive compounds and antioxidant capacity in a thin layer of physalis (Physalis peruviana L.) pulp.

Physalis peruviana L. fruits are rich in bioactive compounds with health benefits. Processing of physalis into pulp with further dehydration has been proposed as a method to increase shelf life and preserve bioactive compounds. Here, the effect of three drying methods on the physico-chemical properties, color, antioxidant capacity, tocopherol and fatty acids content of physalis pulp thin layers were evaluated. The radical scavenging activity showed higher antioxidant activity at high temperatures rather than at low temperatures. Both, DPPH and ORAC assay showed a high antioxidant capacity of the physalis pulp. Chromatic parameters as well as Chroma and Hue angle were affected by drying temperature, which contributed to the discoloring of physalis pulp during this process. Based on these results, both convective drying and infrared drying at 80 °C were proved to be viable drying options for physalis pulp.

Antioxidant, functional properties and health-promoting potential of native South American berries: a review.

Nowadays berries are globally recognized to be among the healthiest foods because they contain diverse and abundant bioactive compounds. Among these are phenolic acids, flavonoids, and anthocyanins, which are known to have beneficial health effects. South America, particularly southern Chile, is covered by a diversity of insufficiently studied and underexploited native berry species. In this review we summarize all the available literature on the phenolic composition, antioxidant activity, bioaccessibility, and biological activity of five native South American berries: calafate, maqui, murta, arrayán, and chequén. The potential of these native berries for promoting human health and as source of bioactive substances is remarkable. Bioactive compounds, mainly anthocyanins, and in less abundance flavonoids and phenolic acids, show strong antioxidant effects. Some of these constituents are bioaccessible and bioavailable, and exert anticancer, antimicrobial, and anti-inflammatory activities as well as inhibitory effects against enzymes involved in metabolic syndromes. Given the potential of native South American berries to promote health, more work is still needed to understand fully the potential beneficial effects of the consumption of these berries on human health. © 2020 Society of Chemical Industry.

Health-promoting activities of edible seaweed extracts from Chilean coasts: assessment of antioxidant, anti-diabetic, anti-inflammatory and antimicrobial potential / Actividades promotoras de la salud de extractos de algas comestibles de las costas chilenas: evaluación del potencial antioxidante, antidiabético, antiinflamatorio y antimicrobiano

ABSTRACT The aim of this study was to evaluate the antioxidant, antidiabetic, anti-inflammatory and antimicrobial activities of three edible seaweed extracts from Chilean coasts: Pyropia orbicularis, Ulva spp, and Durvillaea antarctica. Seaweed extracts in methanol and 70% acetone were performed to evaluate antioxidant and antidiabetic activities, whereas 60% methanol was used to measure anti-inflammatory and antimicrobial activities. Acetone extracts from D. antarctica had the highest total phenolic content and consequently exhibited the strongest antioxidant activity, while methanol extract of this seaweed presented the highest α-glucosidase inhibition (IC50= 0.004 mg mL-1). In the tests against E. coli and Penicillium sp., the extracts obtained from Ulva spp. were the most effective and exhibited the maximum anti-inflammatory effect against phorbol 12-myristate 13-acetate irritant agent (61.8% inhibition) in mice. Results indicated that all evaluated Chilean seaweed extracts are promising candidates for application in functional foods and in the pharmaceutical industry.

RESUMEN El objetivo de este estudio fue evaluar las actividades antioxidantes, antidiabéticas, antiinflamatorias y antimicrobianas de los extractos de tres algas marinas comestibles de las costas Chilenas (Pyropia orbicularis, Ulva spp. y Durvillaea antarctica). Se realizaron extractos de algas marinas en metanol y acetona al 70% para evaluar las actividades antioxidantes y antidiabéticas, mientras que el metanol al 60% se usó para actividades antiinflamatorias y antimicrobianas. Los extractos de acetona de D. antarctica tuvieron el mayor contenido de fenoles totales (TPC) y, en consecuencia, exhibieron la mayor actividad antioxidante, mientras que el extracto metanólico de estas algas presentó la mayor inhibición de la α-glucosidasa (IC50= 0,004 mg mL-1). En las pruebas contra E. coli y Penicillium sp., los extractos obtenidos de Ulva spp., actuaron como los más efectivos y exhibieron el máximo efecto antiinflamatorio contra el agente irritante de forbol 12-miristato 13-acetato (TPA) (inhibición del 61,8%) en ratones. Por lo tanto, los resultados indican que todos los extractos de algas chilenas evaluados pueden ser candidatos prometedores para su aplicación en alimentos funcionales y en las industrias farmacéuticas.

Effects of drying processes on composition, microstructure and health aspects from maqui berries.

The aim of this study is to determine the effects of different drying methods, including freeze drying (FD), convective drying, sun drying, infrared drying and vacuum drying (VD), on the chemical composition and microstructure of maqui berries as well as their anti-inflammatory and antidiabetic activities. Results showed that all dried samples have high unsaturated fatty acids contents (up to 83%) and high total dietary fiber contents (above 50%). Also, one hundred grams of dried berries provide between 11 and 21% of the recommended daily intake of α-tocopherol. Moreover, all dried maqui extracts reduced topical inflammation in treated mice. The highest anti-inflammatory effect against phorbol 12-myristate 13-acetate was found for VD and FD samples. Also, all dried maqui extracts showed antidiabetic activity by inhibiting α-glucosidase activity. The highest α-glucosidase inhibition activity was found for FD samples. The different biological activities of the dried maqui berries were related to differences in the extractability of metabolites due to microstructural changes during drying. The results indicated the potential use of dried maqui as a food ingredient with high unsaturated fatty acids, dietary fiber and α-tocopherol or as a natural extract with therapeutic agents.

Nutritional and organoleptic properties of murta (Ugni molinae Turcz) berries impregnated with Lactobacillus casei var. rhamnosus and dehydrated by different methods.

This work evaluated nutritional and organoleptic properties of murta, a Chilean native berry, impregnated with Lactobacillus casei var. rhamnosus and dehydrated by different methods: freeze- (FD), convective- (CD) and vacuum- (VD) drying. Scanning electron microscopy revealed that L. casei localized at the peduncle and near the peduncle of the impregnated fruit. Murta enriched with probiotics contained higher L. casei viable counts after dehydration with FD compared to CD and VD methods. Overall, drying resulted in a decrease in crude fibre and phenolic compounds, which was attributed to L. casei metabolic activity suggesting that murta berries could act as prebiotics for L. casei. Among drying methods, L. casei enriched FD murta presented less alterations in the microstructure, less drying-induced damage and obtained a higher sensory acceptability score than CD and VD murta. Taken together, these results will contribute to the development of functional foods from regional products improving local economy.

Root inoculation of green bell pepper (Capsicum annum) with Bacillus amyloliquefaciens BBC047: effect on biochemical composition and antioxidant capacity.

BACKGROUND: Consumption of bell peppers is recommended because of their bioactive compound content and their positive effects on health. Growth-promoting rhizobacteria are popular because of their ability to promote plant growth by improving the fixation of nutrients or by inducing a systemic response. Green bell pepper (Capsicum annum) roots were inoculated with an autochthonous strain of Bacillus amyloliquefaciens, at different stages of development: T1, inoculation in the seedbed before transplant; T2, inoculation at and after transplant; T3, inoculation in the seedbed, at and after transplant. Bell pepper plants without inoculation were considered as control. Physicochemical composition and antioxidant activity of the fruits were measured to select the best treatment. RESULTS: T1 increased crude proteins, fat, Ca, Fe, vitamin C, total phenolic content, antioxidant capacity by DPPH and by ORAC. On the other hand, T1 decreased reducing sugars, K and Cu content. No significant differences for total carbohydrates, ash and photosynthetic pigments were found. CONCLUSION: Inoculated green bell peppers have enhanced its functional value and could be considered as an important source of bioactive compounds with elevated antioxidant activity. © 2019 Society of Chemical Industry.

Drying kinetics of probiotic-impregnated murta (Ugni molinae T.) berries.

The aim of this study was to evaluate dehydrated murta berries enriched with probiotic (Lactobacillus casei var. rhamnosus) bacteria. L. casei was incorporated to fresh murta by vacuum impregnation at alternative conditions (pressure 50, 150 and 300 mbar; time 5, 10 and 15 min; temperature 20 ± 0.2 °C) and impregnated murta samples were dehydrated by two drying methods at 40 °C, vacuum and convective drying. Both drying processes were modeled by three mathematical models (Weibull, Page and modified Page). According to the statistical tests applied, the Weilbull model obtained the best-fit quality on experimental data. Effective moisture diffusivity varied between 1.23-1.75 × 10-10 m2/s and 1.16-1.44 × 10-10 m2/s for vacuum and convective drying, respectively. After impregnation, murta berries contained approximately 107 CFU/g L. casei although maximum counts were found at 150 mbar for 15 min. Drying decreased L. casei viability in 1.5-1.9 log and 0.5-1.2 log for vacuum and convective drying, respectively. Thus, impregnation at 150 mbar for 15 min followed by convective drying at 40 °C appears as the method of choice to produce probiotic enriched murta berries that can be commercialized as probiotic dried snacks.

Antifungal activity of proteolytic fraction (P1G10) from (Vasconcellea cundinamarcensis) latex inhibit cell growth and cell wall integrity in Botrytis cinerea.

The aim of this study was to determine the antifungal activity of the proteolytic fraction P1G10 from Vasconcellea cundinamarcencis (ex-Carica candamarcensis) against Botrytis cinerea, the causative agent of pre- and postharvest damaging disease in fruit and vegetables. The survival of B. cinerea at different concentrations of P1G10 showed that 1 mg/mL inhibited 50% of mycelium growth after 72 h incubation. The kinetic of growth inhibition fits the Weibull distribution function, and the data was confirmed by the IC50 survival assay. The study shows that P1G10 inhibits conidia germination and germ tube elongation of B. cinerea relative to untreated conidia. Hypersensitivity to cell wall-perturbing agents (Calcofluor white and Congo red) was observed in mycelium cells treated with P1G10. In addition, P1G10 exhibited inhibitory effect on the adhesion of conidia, provoked alterations in membrane integrity and induced production of reactive oxygen species accompanied by cellular damage. Our results highlight the effect of P1G10 on mycelium growth, cell wall alterations, membrane integrity and adhesion. P1G10 emerges as promising antifungal to control disease causing agents in the food agroindustry.

Phytochemical components and amino acid profile of brown seaweed Durvillaea antarctica as affected by air drying temperature.

The effects of different drying temperatures between 40 and 80 °C on bioactive constituents and antioxidant activity of edible sub Antarctic brown seaweed, Durvillaea antarctica were studied. Dietary fibre, amino acids profile, pigments (chlorophyll and carotenoids), vitamin E, total phenolics and total flavonoids as well as antioxidant activity were determined, beside a measurement of the chromatic coordinates. The brown seaweed D. antarctica had a high content of dietary fibre and was rich in essential amino acids and drying between 40 and 80 °C did not influence significantly dietary fibre content nor the level of essential amino acids that remained around 44%. However, a significant degradation of the chlorophyll pigments was observed with the lowest level of the initial chlorophyll content occurring at 60 °C (59%). Total carotenoids content was stable during drying between 50 and 70 °C. Vitamin E showed no significant loss during drying at any of the assayed temperatures, which could be due to its occurrence within the lipid fraction. Drying at 40 °C imparted a darker brown colour to the seaweed, while a lighter brown colour was acquired as drying temperature increased. The greatest loss in total phenolics content occurred at 60 °C, while total flavonoids content showed a significant reduction, which declined as drying temperature increased. According to the experimental results, phenolics and flavonoids could be considered as an important source of bioactive compounds with relatively high antioxidant activity. Thus D. antarctica may satisfy the requirements for development of functional foods.

Evaluation of phenolic profiles and antioxidant capacity of maqui (Aristotelia chilensis) berries and their relationships to drying methods.

BACKGROUND: Five drying methods (freeze, convective, sun, infrared, and vacuum drying) were applied to maqui berries to establish their effect on phenolic compounds and antioxidant capacity. Total phenolic, total flavonoid, and total anthocyanin contents were measured by spectrophotometry, anthocyanin and phenolic profiles were analyzed by chromatography, and the antioxidant capacity was determined. This study is probably the first to demonstrate the variation and stability of bioactive compounds from maqui berries after applying different drying methods. RESULTS: The highest content of phenolic and antioxidant compounds was obtained by using the freeze-drying method compared with fresh samples (P < 0.05). Eight anthocyanins were identified in all dehydrated maqui samples. Compared with fresh maqui, freeze-dried samples retained 73% and 64% of delphinidin and cyanidin derivatives respectively. Sun- and vacuum-dried samples conserved some phenolic acids. Vacuum-dried maqui retained a higher amount of free flavonols. CONCLUSION: This study demonstrated that the application of any drying method results in a final product with good levels of phenolic compounds. © 2018 Society of Chemical Industry.