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.

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.

Experimental and Numerical Study of a Turbulent Air-Drying Process for an Ellipsoidal Fruit with Volume Changes.

It is common in the numerical simulations for drying of food to suppose that the food does not experience a change of volume. The few numerical studies that include volume changes assume that the shrinkage occurs symmetrically in all directions. Therefore, this effect has not been fully studied, and it is known that not considering it can be detrimental for the accuracy of these simulations. The present study aims to develop a three-dimensional model for the simulation of fruits that includes the volume changes but also takes into consideration the asymmetry of the shrinkage. Physalis peruviana is taken as the subject of study to conduct experiments and imaging analyses that provided data about the drying kinetics and asymmetric shrinkage mode. The effective diffusion coefficient is found to be between 10-12 m2 s-1 and 1.75 × 10-9 m2 s-1. The shrinkage occurs essentially in only one direction, with an average velocity of 8.3 × 10-5 m/min. A numerical modelling scheme is developed that allows including the shrinkage effect in computer simulations. The performance of the model is evaluated by comparison with experimental data, showing that the proposed model decreases more than 4 times the relative error with respect to simulations that do not include volume changes. The proposed model proves to be a useful method that can contribute to more accurate modeling of drying processes.

Honeybee Pollen From Southern Chile: Phenolic Profile, Antioxidant Capacity, Bioaccessibility, and Inhibition of DNA Damage.

Honeybee pollen (HBP) chemical composition is highly variable conforming to the floral and geographical origin of the pollen grains. The beneficial effects and functional properties of the HBP are well-known and have been mainly attributed to their high content of antioxidant polyphenols. In this work, twelve HBPs samples from the Southern region of Chile (X Región de Los Lagos) were characterized for the first time according to their botanical origin, phenolic composition, and antioxidant activity. The in vitro gastrointestinal digestion assay was done to simulate the human upper digestive tract. Selected honeybee pollen extracts (HBPEs) were assessed as bioaccessible fractions during an in vitro gastrointestinal digestion. Contents of phenolic compounds, antioxidant capacity, and recovery index of quercetin, myricetin, and cinnamic acid were monitored in different steps of gastrointestinal digestion. Furthermore, the protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals was evaluated. The introduced species Brassica rapa L. (Brassicaceae), Lotus pedunculatus Cav. (Fabaceae), and Ulex europaeus L. (Fabaceae) predominated in all the HBPs analyzed, while the native species Buddleja globosa Hope (Scrophulariaceae), Luma apiculata (DC.) Burret (Myrtaceae), Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae) and Eucryphia cordifolia Cav. (Cunoniaceae) appeared less frequently. The content of polyphenols and antioxidant capacity in HBPEs achieved full bioaccessibility at the end of the intestinal digestion step. However, results obtained by a state-of-the-art technique (i.e. HPLC-DAD) demonstrated relatively low values of bioaccessible quercetin and cinnamic acid after the digestion process. In contrast, myricetin showed a high bioaccessibility in the intestinal digestion steps. The protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals showed promising results (up to 91.2% protection). In conclusion, HBPs from the X Region de Los Lagos are rich sources of phenolic antioxidants that protect DNA from strand breakage. Therefore, the potential of HBPEs in preventing gastric and/or intestinal cancer should be further considered.

Effect of drying methods on drying kinetics, energy features, thermophysical and microstructural properties of Stevia rebaudiana leaves.

BACKGROUND: Stevia leaves were subjected to convective hot-air, infrared and vacuum drying at 40, 60 and 80 °C, followed by an assessment of thermophysical properties and microstructure, along with drying kinetics modelling and evaluation of energy features for all drying operations. RESULTS: Effective moisture diffusivity (Deff ) showed dependency on temperature with values ranging from 1.08 × 10-12 to 7.43 × 10-12  m2  s-1 for convective drying, from 0.71 × 10-12 to 6.60 × 10-12  m2  s-1 for infrared drying, and from 1.29 × 10-12 to 5.39 × 10-12  m2  s-1 for vacuum drying. The thermal properties of the dried Stevia leaves under different drying conditions showed values of density, specific heat, thermal diffusivity, thermal conductivity and thermal effusivity ranging from 95.6 to 116.2 kg m-3 , 3050 to 3900 J kg-1  K-1 , 4.28 × 10-7 to 5.60 × 10-7  m2  s-1 , 0.16 to 0.23 W m-1  K-1 and 244 to 305 W s0.5  m-2  K-1 , respectively. As for microstructure, convective hot-air drying showed better preserved leaf characteristics, compared to infrared- and vacuum-drying, whereby scanning electron microscopy (SEM) image analysis also revealed noticeable differences at higher temperatures. Statistical analysis showed that the Midilli-Kuçuk model fitted best the experimental data of drying curves (0.961 < r2 < 0.999, 0.000064 < SSE < 0.005359, and 0.000074 < χ2 < 0.006278). Comparison of the drying methods with respect to energy features showed that convective drying at 80 °C led to lowest specific energy consumption (61.86 kW h kg-1 ) with highest efficiency (8.5%). CONCLUSION: The results of this study contribute to a better understanding of the drying behaviour and showed that thermophysical properties of dried Stevia leaves and energy features are affected by drying methods. © 2021 Society of Chemical Industry.

Total phenolics, anthocyanin profile and antioxidant activity of maqui, Aristotelia chilensis (Mol.) Stuntz, berries extract in freeze-dried polysaccharides microcapsules.

The effect of different polysaccharides combinations on the stability of maqui extract was studied in order to design functional foods, dietary supplements or natural colorants. Encapsulation by freeze-drying using maltodextrin, gum Arabic and inulin at 10, 20 and 30% was performed and phenolics, anthocyanin, antioxidant capacity and color difference of the microcapsules were determined. The stability of the bioactives after 60 days storage at 25 °C was also evaluated, along with analysis of aw, adsorption isotherm, and microstructure to characterize the powders. 10% encapsulating polysaccharide produced best results, with maltodextrin leading to highest process efficiency, while the mixture of maltodextrin/inulin in equal proportion led to highest retention of polyphenols (91.1%) and anthocyanin (98.8%) during storage. The inulin microcapsules retained 94.1% of its antioxidant capacity compared to 25.3% for the freeze-dried maqui powder. Concentration level and polysaccharide matrix of encapsulating agent significantly affect retention of bioactives in the microcapsules.

Survival of Spray-Dried Rhodotorula mucilaginosa Isolated from Natural Microbiota of Murta Berries and AntagonisticEffect on Botrytis cinerea.

The aim of this study is to evaluate the survival rate and effective antagonistic activity against Botrytis cinerea, responsible for grey mould on harvested fruits and vegetables, of yeast Rhodotorula mucilaginosa, isolated and identified from the natural microbiota of murta (Chilean guava) berries, after spray drying at different inlet air temperatures, mass per volume ratio of encapsulating agent (maltodextrin) and feed flow rates. The 100% survival of the yeast was obtained after spray drying with 18% maltodextrin at 130 °C inlet temperature and a feed flow rate of 9.25 mL/min. The dried yeast obtained under such conditions had the highest antagonistic activity in vitro and in vivo on apples, which showed that spray drying is a valid method to produce active dried cells of R. mucilaginosa that can be used for biocontrol of grey mould spoilage. It was also found that the encapsulating agent maltodextrin improved the in vitro antagonistic activity of R. mucilaginosa.

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.

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.

Effect of high hydrostatic pressure on rheological and thermophysical properties of murtilla (Ugni molinae Turcz) berries.

Effects of high hydrostatic pressure (HHP) on rheological and thermophysical properties of murtilla berries were evaluated after pressure treatments for 5 min between 100 and 500 MPa. Differential scanning calorimetry was employed to measure specific heat capacity. HHP caused a significant decrease in specific heat and density, while thermal diffusivity did not changed significantly. Thermal conductivity showed a slight increase upon HHP treatment. Apparent viscosity increased significantly above 200 MPa HHP treatment. Apparent viscosity of treated samples between 200 and 400 MPa did not differ significantly and the increase was significant at 500 MPa. Herschel-Bulkley, Bingham and Ostwald de Waele models were used to describe the rheological behaviour of murtilla purée, and Ostwald de Waele model gave the best fit for the experimental data.

Stevia rebaudiana Leaves: Effect of Drying Process Temperature on Bioactive Components, Antioxidant Capacity and Natural Sweeteners.

Stevia leaves are usually used in dried state and undergo the inevitable effect of drying process that changes the quality characteristics of the final product. The aim of this study was to assess temperature effect on Stevia leaves through analysis of relevant bioactive components, antioxidant capacity and content of natural sweeteners and minerals. The drying process was performed in a convective dryer at constant temperatures ranging from 30 to 80 °C. Vitamin C was determined in the leaves and as expected showed a decrease during drying proportional to temperature. Phenolics and flavonoids were also determined and were found to increase during drying below 50 °C. Antioxidant activity was determined by DPPH and ORAC assays, and the latter showed the highest value at 40 °C, with a better correlation with the phenolics and flavonoids content. The content of eight natural sweeteners found in Stevia leaves was also determined and an increase in the content of seven of the sweeteners, excluding steviol bioside, was found at drying temperature up to 50 °C. At temperatures between 60 and 80 °C the increase in sweeteners content was not significant. Stevia leaves proved to be an excellent source of antioxidants and natural sweeteners.

Influence of high hydrostatic pressure on quality parameters and structural properties of aloe vera gel (Aloe barbadensis Miller).

The aim of this work was to study the effect of high hydrostatic pressure (HHP) on colour, dietary fibre, vitamin C content, polysaccharides content, physico-chemical and structural properties of aloe vera gel at three pressure levels (300, 400 and 500 MPa for 3 min) after 35 days of storage at 4 ± 1 °C. The results showed that HHP exerted a clear influence on most of the quality parameters studied. Moisture, protein and fat contents did not show changes with an increasing pressure. Ash, crude fibre and carbohydrates content increased with increasing pressure. Vitamin C content did not show significant differences after 35 days of storage. The variation of colour in the samples increased at 500 MPa. Total dietary fibre, water holding capacity and firmness increased with pressure. However, all HHP-treated samples presented a decrease in hydration ratio and polysaccharides content; and also minor alterations in the structural properties were produced at HHP of 300-500 MPa, resulting in a high quality gel.

Influence of air-drying temperature on drying kinetics, colour, firmness and biochemical characteristics of Atlantic salmon (Salmo salar L.) fillets.

In this work the drying kinetics of Atlantic salmon (Salmo salar L.) fillets and the influence of air drying temperature on colour, firmness and biochemical characteristics were studied. Experiments were conducted at 40, 50 and 60°C. Effective moisture diffusivity increased with temperature from 1.08×10(-10) to 1.90×10(-10) m(2) s(-1). The colour difference, determined as ΔE values (from 9.3 to 19.3), as well as firmness (from 25 to 75 N mm(-1)) of dried samples increased with dehydration temperature. The lightness value L(∗) and yellowness value b(∗) indicated formation of browning products at higher drying temperatures, while redness value a(∗) showed dependence on astaxanthin value. Compared with fresh fish samples, palmitic acid and tocopherol content decreased in a 20% and 40%, respectively, with temperature. While eicosapentaenoic acid (EPA) content remained unchanged and docosahexaenoic acid (DHA) content changed slightly. Anisidine and thiobarbituric acid values indicated the formation of secondary lipid oxidation products, which is more relevant for longer drying time than for higher drying temperatures.

Stevia rebaudiana Bertoni, source of a high-potency natural sweetener: A comprehensive review on the biochemical, nutritional and functional aspects.

Stevia rebaudiana Bertoni, an ancient perennial shrub of South America, produces diterpene glycosides that are low calorie sweeteners, about 300 times sweeter than saccharose. Stevia extracts, besides having therapeutic properties, contain a high level of sweetening compounds, known as steviol glycosides, which are thought to possess antioxidant, antimicrobial and antifungal activity. Stevioside and rebaudioside A are the main sweetening compounds of interest. They are thermostable even at temperatures of up to 200°C, making them suitable for use in cooked foods. S. rebaudiana has a great potential as a new agricultural crop since consumer demand for herbal foods is increasing and proximate analysis has shown that Stevia also contains folic acid, vitamin C and all of the indispensable amino acids with the exception of tryptophan. Stevia cultivation and production would further help those who have to restrict carbohydrate intake in their diet; to enjoy the sweet taste with minimal calories.

Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices.

The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80°C, as well as at air velocities of 0.5, 1.0 and 1.5ms(-1). Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30×10(-9)m(2)s(-1) at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80°C. The DPPH-radical scavenging activity at 40°C and 0.5ms(-1) showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis.