Design of Experiments for Optimizing Ultrasound-Assisted Extraction of Bioactive Compounds from Plant-Based Sources.

Plant-based materials are an important source of bioactive compounds (BC) with interesting industrial applications. Therefore, adequate experimental strategies for maximizing their recovery yield are required. Among all procedures for extracting BC (maceration, Soxhlet, hydro-distillation, pulsed-electric field, enzyme, microwave, high hydrostatic pressure, and supercritical fluids), the ultrasound-assisted extraction (UAE) highlighted as an advanced, cost-efficient, eco-friendly, and sustainable alternative for recovering BC (polyphenols, flavonoids, anthocyanins, and carotenoids) from plant sources with higher yields. However, the UAE efficiency is influenced by several factors, including operational variables and extraction process (frequency, amplitude, ultrasonic power, pulse cycle, type of solvent, extraction time, solvent-to-solid ratio, pH, particle size, and temperature) that exert an impact on the molecular structures of targeted molecules, leading to variations in their biological properties. In this context, a diverse design of experiments (DOEs), including full or fractional factorial, Plackett-Burman, Box-Behnken, Central composite, Taguchi, Mixture, D-optimal, and Doehlert have been investigated alone and in combination to optimize the UAE of BC from plant-based materials, using the response surface methodology and mathematical models in a simple or multi-factorial/multi-response approach. The present review summarizes the advantages and limitations of the most common DOEs investigated to optimize the UAE of bioactive compounds from plant-based materials.

Antioxidant activity of kafirin hydrolysates on UVB irradiated human keratinocyte cells and in silico identification.

BACKGROUND: Ultraviolet B (UVB) causes photoaging of the skin, the appearance of wrinkles, spots, and alteration of the skin barrier. The main cells in the most superficial layer of the skin are the keratinocytes; these cells play an important role in protecting this organ. OBJECTIVE: The present study aimed to investigate the antioxidant activity of the hydrolysates from kafirin to inhibit UVB-induced responses in human keratinocytes cells (HaCaT). METHODS: Kafirin hydrolysates were produced by enzymatic hydrolysis with alcalase. The activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in the HaCaT cell line in the presence of UVB and the effects of the hydrolysates against the UVB-induced response were evaluated. Furthermore, the peptides that were generated by hydrolysis were identified in silico using the BIOPEP database. RESULTS: Two protein sequences were identified (α-kafirin and the precursor protein of α-kafirin), in the kafirin extract. A degree of hydrolysis of 18.8% was obtained by hydrolyzing the kafirin extract with alcalase. The kafirin hydrolysates avoided the decrease in endogenous antioxidant enzymes such as SOD, CAT, and GPx reducing the oxidative stress generated by UVB. Using the BIOPEP-UWM database, we found 102 peptide sequences, and it has shown that the peptides have a large amount of hydrophobic amino acids such as proline, alanine, and glutamine, and amino acids with high antioxidant capacity. CONCLUSION: These results suggest that the kafirin hydrolysates can be used as antioxidant agents to ameliorate UVB-induced skin keratinocytes cells' response in vitro, providing an alternative against UVB-induced photoaging.

Postharvest application effect of agave fructans on anthracnose disease, defense-related enzyme activities, and quality attributes in avocado fruit.

The postharvest application of high degree of polymerization agave fructans (HDPAF) was tested, evaluating anthracnose disease, defense-related enzyme activities, and quality attributes in avocado fruit. Application of a 20% HDPAF solution showed a reduction in anthracnose severity (60%) and incidence (34%) compared to the other concentrations evaluated and the water-treated control. Polyphenoloxidase activity increased 4.6 times more 24 h after treatment. In addition, peroxidase and phenylalanine ammonia-lyase enzyme activity was 4.34 and 1.7 times higher than the control at 0.5 h after treatment. HDPAF retrieves the deceleration of both firmness loss and physiological weight loss compared to the control. Regarding quality parameters such as color, pH, total soluble solids, and titratable acidity, no significant differences were observed between treatments compared to the control; therefore, these parameters were not negatively affected by HDPAF treatments, but a positive effect on the induction of the defense system is shown.

Ultrasound-Assisted Extraction of Phenolic Compounds from Psidium cattleianum Leaves: Optimization Using the Response Surface Methodology.

In this study, conditions for the ultrasound-assisted extraction (UAE) of soluble polyphenols from Psidium cattleianum (PC) leaves were optimized using response surface methodology (RSM) by assessing the effect of extraction time (XET = 2, 4, and 6 min), sonication amplitude (XSA = 60, 80, and 100%), and pulse cycle (XPC = 0.4, 0.7, and 1 s). Furthermore, the optimized UAE conditions were compared with a conventional aqueous-organic extraction (AOE) method for extracting total phenolics; moreover, a phenolic profile using HPLC and antioxidant activity (DPPH, ABTS, and FRAP) were also compared. According to the RSM, the best conditions for UAE to extract the highest soluble polyphenol content and yield (158.18 mg/g dry matter [DM] and 15.81%) include a 100% sonication amplitude for 4 min at 0.6 s of pulse cycle. The optimal UAE conditions exhibited an effectiveness of 1.71 times in comparison to the AOE method for extracting total phenolics, in 96.66% less time; moreover, PC leaf extracts by UAE showed higher antioxidant values than AOE. Additionally, gallic, protocateic, chlorogenic, caffeic, coumaric, trans-cinnamic, 4-hydroxybenzoic, and syringic acids, as well as kaempferol were identified in PC leaves under UAE. PC leaf extracts are widely used for therapeutic and other industrial purposes; thus, the UAE proves to be a useful technology with which to improve the yield extraction of PC leaf phytochemicals.

Conversion of RNA Aptamer into Modified DNA Aptamers Provides for Prolonged Stability and Enhanced Antitumor Activity.

Aptamers, synthetic single-strand oligonucleotides that are similar in function to antibodies, are promising as therapeutics because of their minimal side effects. However, the stability and bioavailability of the aptamers pose a challenge. We developed aptamers converted from RNA aptamer to modified DNA aptamers that target phospho-AXL with improved stability and bioavailability. On the basis of the comparative analysis of a library of 17 converted modified DNA aptamers, we selected aptamer candidates, GLB-G25 and GLB-A04, that exhibited the highest bioavailability, stability, and robust antitumor effect in in vitro experiments. Backbone modifications such as thiophosphate or dithiophosphate and a covalent modification of the 5'-end of the aptamer with polyethylene glycol optimized the pharmacokinetic properties, improved the stability of the aptamers in vivo by reducing nuclease hydrolysis and renal clearance, and achieved high and sustained inhibition of AXL at a very low dose. Treatment with these modified aptamers in ovarian cancer orthotopic mouse models significantly reduced tumor growth and the number of metastases. This effective silencing of the phospho-AXL target thus demonstrated that aptamer specificity and bioavailability can be improved by the chemical modification of existing aptamers for phospho-AXL. These results lay the foundation for the translation of these aptamer candidates and companion biomarkers to the clinic.

Ultrasound-Assisted Extraction of Total Acetogenins from the Soursop Fruit by Response Surface Methodology.

The soursop fruit or Annona muricata (A. muricata) fruit is recognized by its bioactive compounds and acetogenins (ACG) are among the most important. The effect of ACGs, with greater importance in health, is that they present anti-tumor activity; however, the methods of extraction of ACGs are very slow and with a high expenditure of solvents. To our knowledge, there is no report of an optimal method for the extraction of acetogenins from the Annonaceae family by ultrasound-assisted extraction (UAE); therefore, the aim was to find the best UEA conditions of acetogenins from A. muricata fruit (peel, pulp, seed, and columella) by using response surface methodology. The effect of amplitude (40%, 70%, and 100%), time (5, 10, and 15 min), and pulse-cycle (0.4, 0.7, and 1 s) of ultrasound at 24 kHz was evaluated on the total acetogenin content (TAC). Optimal extraction conditions of acetogenins (ACGs) with UEA were compared with the extraction of ACGs by maceration. The optimal UEA conditions in the A. muricata pulp and by-products were dependent on each raw material. The highest TAC was found in the seed (13.01 mg/g dry weight (DW)), followed by the peel (1.69 mg/g DW), the pulp (1.67 mg/g DW), and columella (1.52 mg/g DW). The experimental TAC correlated well with the model (Adjusted R2 with values between 0.88 and 0.97). The highest effectiveness in ACG extraction was obtained in seeds and peels using UEA compared to extraction by maceration (993% and 650%, respectively). The results showed that A. muricata by-products are an important source of ACGs and that UAE could be a viable alternative, with high potential for large-scale extraction.

Effect of low-fat diets enriched with fruit purees on the biochemical markers of metabolic syndrome analogy induced-rats / Efecto de dietas bajas en grasa enriquecida con purés de frutas sobre marcadores bioquímicos en ratas inducidas con analogia a sindrome metabólico

Fruit purees can be added to diet as alternative sources of bioactive compounds for the prevention and/or improvement of the complications of metabolic syndrome. In this work we evaluated the effect of the intake of low-fat diets enriched with fruit purees (guava-strawberry, guava-blackberry, guava-soursop, guava-passion fruit) on the body weight and biochemical markers in metabolic syndrome analogy (MSA)-induced rats. The rats (n=6 for each treatment) were induced with a high fat diet and were injected with streptozotocin, one dose every week for 4 consecutive weeks after fasting overnight, then healthy rats were fed with standard diet and MS rats were fed with standard diet plus each of the fruit puree, for 4 weeks. As novel findings, the diet enriched with fruit purees was associated with a reduction in body weight (~13-21 %) and a control in the metabolism of glucose by decreasing plasma glucose (~5963 %). Also, there was a reduction in the total cholesterol, triacylglycerols, low-density lipoproteins, and low enzymatic activities of alanine aminotransferase, alkaline phosphatase and γ-glutamyl transferase, useful metabolites in the control of inflammatory processes in the liver. A notable improvement in the liver morphology was observed indicating that the treatments had a hepatoprotective effect. The diet enriched with guava-blackberry puree caused the best results on most biochemical markers of MS rats. Therefore, diets enriched with fruit purees can be an alternative for MS individuals for the control and improvement of the complications caused by this syndrome.

Los purés de frutas se pueden agregar a la dieta como fuentes alternativas de compuestos bioactivos para la prevención y / o mejora de las complicaciones del síndrome metabólico. En este trabajo evaluamos el efecto de la ingesta de dietas bajas en grasas, enriquecidas con purés de frutas (guayaba-fresa, guayaba-mora, guayaba-guanábana, guayaba-maracuyá) sobre el peso corporal y los marcadores bioquímicos en el síndrome metabólico (SM) inducido en ratas. Las ratas (n = 6 para cada tratamiento) fueron inducidas con una dieta alta en grasas y se les inyectó estreptozotocina, una dosis cada semana durante 4 semanas consecutivas después de ayunar durante la noche. Luego, las ratas sanas fueron alimentadas con una dieta estándar; y las ratas con SM fueron alimentadas con dieta estándar más cada uno de los purés de frutas, durante 4 semanas. Como hallazgos novedosos, la dieta enriquecida con purés de frutas se asoció con una reducción en el peso corporal (~ 13-21 %) y un control en el metabolismo de la glucosa al disminuir la glucosa en plasma (~ 59-63 %). Además, hubo una reducción en el colesterol total, triacilgliceroles, lipoproteínas de baja densidad, y bajas actividades enzimáticas de alanina aminotransferasa, fosfatasa alcalina y gama-glutamil transferasa, metabolitos útiles en el control de los procesos inflamatorios en el hígado. Se observó una mejora notable en la morfología del hígado, lo que indica que los tratamientos tuvieron un efecto hepatoprotector. La dieta enriquecida con puré de guayaba y mora causó los mejores resultados en la mayoría de los marcadores bioquímicos de las ratas con SM. Por lo tanto, las dietas enriquecidas con purés de frutas pueden ser una alternativa para las personas con SM, para el control y la mejora de las complicaciones causadas por este síndrome.

Evaluation of nutritional characteristics and bioactive compounds of soursop-yoghurt and soursop-frozen dessert.

The nutritional quality, sensory attributes, polyphenols and acetogenins content in yoghurt and frozen dessert formulated with soursop pulp were investigated. The addition of soursop pulp to yoghurt and frozen dessert improved the sensory attributes and the nutritional quality of soursop dairy products resulting in a composition of 0.92 and 2.17% of dietary fiber, 11.25 and 9.84 mg/100 g of vitamin C as well as 243.02 and 490.98 mg/100 g of total polyphenols, respectively. Acetogenins were extracted from both dairy products using maceration, sonication, microwave and Soxhlet. Sonication showed to be faster and safer than the other methods for acetogenins extraction. Higher annonacin (an acetogenin) content was found in yoghurt (38 ng/g) than in frozen dessert (15 ng/g). The quantification of bioactive compounds implied the nutraceutical properties to yoghurt and ice cream when they are added with soursop pulp. The results are useful for the consumers seeking healthier foods.

Optimization of Ultrasound-Assisted Extraction of Phenolic Compounds from Annona muricata By-Products and Pulp.

Ultrasound-assisted extraction (UAE) is widely used; however, the efficiency of extraction depends on the raw materials. Therefore, optimization of UAE must be investigated for each type of plant material. By-products from soursop fruit have not been studied as a source of bioactive compounds. In this work, the optimization of UAE conditions (extraction time (5, 10, and 15 min), pulse cycle (0.4, 0.7, and 1 s), and sonication amplitude (40%, 70%, and 100%)) for the extraction of phenolic compounds (soluble, hydrolyzable, condensed tannins, and total polyphenols) from soursop by-products (seed, peel, and columella) and pulp was evaluated using response surface methodology. The optimal conditions for UAE to obtain the highest total polyphenol content from by-products and pulp was dependent on the raw material. Peel resulted in the highest content of total polyphenols (187.32 mg/g dry matter [DM]) followed by columella (164.14 mg/g DM), seed (36.15 mg/g DM), and pulp (33.24 mg/g DM). The yield of polyphenolic content from peel and columella obtained with UAE was higher (32⁻37%) than conventional extraction for 2 h under stirring (14⁻16%). The contents of gallic acid (0.36⁻15.86 µg/g DM), coumaric acid (0.07⁻1.37 µg/g DM), and chlorogenic acid (9.18⁻32.67 µg/g DM) in the different parts of the fruit were higher in the extracts obtained by UAE compared with a conventional extraction method (0.08⁻0.61, 0.05⁻0.08, 3.15⁻13.08 µg/g DM, respectively), although it was dependent on the raw materials. Soursop by-products can be functionally important if they are used to extract bioactive compounds by UAE; a technology with high potential for commercial extraction on a large scale.

Enzyme activity and partial characterization of proteases obtained from Bromelia karatas fruit and compared with Bromelia pinguin proteases.

The enzymatic activity and partial characterization of proteases from Bromelia karatas fruits were evaluated and compared with Bromelia pinguin proteases. The specific activity increased twofold after partial purification in both proteases. Partially purified proteases from Bromelia karatas showed good specific activity at pH 6.0-8.0 and residual activity of 70-100% for 60 min at 37-60 °C, similar to Bromelia pinguin proteases. The K m value of proteases from Bromelia karatas was higher (253.32 µM) than that of Bromelia pinguin proteases (234.94 µM). The use of specific protease inhibitors indicated the presence of cysteine and serine proteases. Proteases with molecular weight of 66.2-97 and 21-31 kDa were detected. Bromelia karatas proteases registered 73% hydrolysis using a soy protein concentrate, similar to the enzyme activity of Bromelia pinguin proteases and commercial bromelain. These results demonstrate that Bromelia karatas proteases could be a potential alternative protease in the food industry.

Optimization of ultrasonic-assisted extraction of phenolic compounds from Justicia spicigera leaves.

A Box-Behnken design (Extraction-time, pulse-cycle, sonication-amplitude) was employed to extract phenolic compounds from Justicia spicigera leaves by ultrasonic-assisted extraction. The muicle leaves extracts were analyzed measuring total phenolic compounds and antioxidant capacity. According to response surface methodology the optimal conditions of ultrasonic-assisted extraction to obtain the highest soluble phenolic content were 2 min (extraction time) for 0.7 s (pulse cycle) at 55% of sonication amplitude. Under these optimal conditions, the total phenolic content was higher when was used ultrasonic-assisted extraction (54.02 mg/g) than stirring (46.46 mg/g) and thermal decoction (47.76 mg/g); however, the antioxidant capacity from J. spicigera extracts did not increase by ultrasonic-assisted extraction. The extracts or aqueous infusions from J. spicigera leaves are used for therapeutic proposes, therefore the ultrasonic-assisted extraction is a useful technology to improve the extraction of phytochemicals from J. spicigera leaves.

In vitro human colonic fermentation of indigestible fraction isolated from lunch menus: impact on the gut metabolites and antioxidant capacity.

The indigestible fraction (IF) isolated from three lunch menus: Modified Mexican Lunch (MM-L), Traditional Mexican Lunch (TM-L) and Alternative Mexican Lunch (AM-L), was studied in terms of antioxidant capacity (AOX) and metabolites produced through fermentation by human intestinal microbiota. IFs were isolated after withstanding in vitro gastrointestinal digestion and total soluble polyphenols (TSP), condensed tannins (CT), hydrolysable polyphenols (HP) and AOX (DPPH, FRAP) were evaluated. AOX, pH and bacterial metabolites profile changes were also monitored during in vitro colonic fermentation. Lunch menus showed differences in IF, TSP, CT and FRAP values (p<.05). TM-L had the highest TSP and CT contents (0.84 and 1.89 g/100 g DW, respectively). Changes in pH and AOX during fermentation were time-dependent and substrate-dependent (p<.05). Butyric acid production was not significantly modified by the IFs (p>.05). Fifty-seven microbiota-produced volatile compounds were detected by SPME-GC-MS. This study shows the potential effects of food habits on bacterial metabolite production.

Changes in the nutritional quality of five Mangifera species harvested at two maturity stages.

BACKGROUND: There are 69 species of edible Mangifera recognized in Southeast Asia. Most of these species have not been characterized for nutritional properties. This paper describes the nutritional quality of the pulp of several Mangifera species - Mangifera casturi, Mangifera lalijiwa, Mangifera odorata, Mangifera zeylanica and two cultivars of Mangifera indica, 'Tommy-Kent' and 'Tommy Atkins' - at two maturity stages. RESULTS: The results showed that nutritional quality varied with maturity stage and among species. The immature pulp of all species had higher content of total dietary fibre, vitamin C, vitamin E, total soluble polyphenols and antioxidant capacity. In mature pulp, the protein, ash, fat, soluble carbohydrate and B vitamin values were higher in all species. The species with the best nutritional quality were, in order from highest to lowest, M. casturi, M. odorata, M. zeylanica, M. indica cultivars and M. lalijiwa. CONCLUSION: The fruit pulp of three species had higher nutritional quality at both maturity stages in comparison with M. indica cultivars. These other Mangifera species can be nutritionally important in communities facing food insecurity and have potential as emerging crops. The decline of these valuable species in their natural habitats is an increasing concern, and their nutritional properties justify greater efforts to protect them. © 2017 Society of Chemical Industry.

Dietary patterns, nutritional profile, and body mass index in Mexican schoolchildren: a cross-sectional study

Childhood obesity is a serious public health problem in Mexico. In this study, childhoodspecific dietary patterns and their relationship with overweight-obesity prevalence, nutrient profiles and types of foods consumed were studied. A descriptive cross-sectional study of 724 randomly selected schoolchildren between 9 to 12 years old from Nayarit State, Mexico was performed. Data on anthropometric characteristics and food intake were recorded. Seven dietary patterns and three specific diets were identified by multivariate analysis. A dietary pattern characterized by high legume, snack and low beverage intake was negatively associated with weight and body mass index. The overall overweight and obesity prevalence was 20.2% and 20.6%, respectively. Diet type significantly influenced (p<0.05) protein, carbohydrates and fat intake but did not show correlation with the overweightobesity status. Simple sugars, candies, pastries and sweetened beverages appeared in all dietary patterns. Dietary patterns in countries with a wide gastronomic diversity should be considered to design preventive nutrition intervention programs(AU)

La obesidad infantil es un problema de salud pública en México. En este trabajo, se estudiaron los patrones dietéticos de escolares mexicanos y su relación con la prevalencia de sobrepeso-obesidad, el perfil de nutrientes y los principales grupos de alimentos consumidos. Se llevó a cabo un estudio transversal descriptivo donde participaron 724 escolares seleccionados al azar de entre 9 a 12 años del Estado de Nayarit, México evaluándose las características antropométricas y la ingesta de alimentos. Siete patrones dietéticos y tres dietas específicas fueron identificados mediante análisis multivariado. Un patrón de dieta caracterizada por una alta ingesta de legumbres y aperitivos junto con una baja ingesta de bebidas azucaradas se asoció negativamente con el peso e índice de masa corporal. La prevalencia de sobrepeso y obesidad fue del 20.2 y 20.6%, respectivamente. El tipo de dieta influyó significativamente (p<0.05) en la ingesta de proteínas, hidratos de carbono y el consumo de grasas, pero no mostró correlación con la condición de sobrepeso-obesidad. Los azúcares simples, dulces, postres y bebidas endulzadas aparecieron en todos los patrones dietéticos. Los patrones dietéticos en los países con una gran diversidad gastronómica podrían ser considerados de interés para diseñar programas de intervención nutricional preventiva(AU)

Effect of high hydrostatic pressure on the polyphenols and antioxidant activity of plantain pulp (Musa paradisiaca AAB).

BACKGROUND: The impact of high-pressure processing (HPP) on the polyphenol (PP) content and antioxidant activity (AOX) of plantain pulp was evaluated. Pressures of 400, 500 and 600 MPa were applied to plantain pulp for 90 and 180 s at room temperature (25 °C). Polyphenoloxidase activity, extractable (EPP) and non-extractable PP (NEPP) contents, flavonoid content and AOX (FRAP, ABTS•+ ) were evaluated. In addition, PP identification was performed using high-performance liquid chromatography. RESULTS: Polyphenoloxidase activity was inhibited after HPP under all of the conditions studied. Increases of 110.80% and 137.40% in EPP content under conditions of 500 MPa/180 s and 600 MPa/90 s were observed with a simultaneous improvement in the AOX with increments of up to 128.71%. The treatment under conditions of 500 MPa/90 s had the highest total PP content, including the highest content of flavonoids (0.22 g ellagic acid equivalents kg-1 dry weight) and the proportion of NEPP that contained hydrolysable PPs (91.12 g gallic acid equivalents kg-1 dry weight with high AOX. The identified PPs included catechin, quercetin, gallic and hydroxybenzoic acids. CONCLUSION: HPP performed at a room temperature can be used for improving the total content of PP compounds in plantain pulp under specific pressure and time conditions. © 2016 Society of Chemical Industry.

Bioaccessibility of polyphenols associated with dietary fiber and in vitro kinetics release of polyphenols in Mexican 'Ataulfo' mango (Mangifera indica L.) by-products.

The biological properties of polyphenol (PP) depend on its bioaccessibility and bioavailability. Therefore, part of PP released from the food matrix in the gastrointestinal tract through enzymatic hydrolysis is at least partially absorbed. The aim of this study is to determine the bioaccessibility of PP associated with dietary fiber (DF) and the kinetics release of PP in mango (Mangifera indica L.) 'Ataulfo' by-products by an in vitro model. Soluble and insoluble DF values were 7.99 and 18.56% in the mango paste and 6.98 and 22.78% in the mango peel, respectively. PP associated with soluble and insoluble DF was 6.0 and 3.73 g GAE per 100 g in the paste and 4.72 and 4.50 g GAE per 100 g in the peel. The bioaccessibility of PP was 38.67% in the pulp paste and 40.53% in the peel. A kinetics study shows a release rate of 2.66 and 3.27 g PP min(-1) in the paste and peel, respectively. The antioxidant capacity of the paste increased as digestion reached a value of 2.87 mmol TE min(-1) at 180 min. The antioxidant capacity of the peel had its maximum (28.94 mmol TE min(-1)) between 90 and 120 min of digestion; it started with a value of 2.58 mmol TE min(-1), and thereafter increased to 4.20 mmol TE min(-1) at 180 min. The major PPs released during the digestion of paste were gallic and hydroxybenzoic acids, while in the peel, they were hydroxycinnamic and vanillic acids. It was concluded that these phenolic compounds are readily available for absorption in the small intestine and exert different potential health benefits.

Effect of the application of 1-methylcyclopropene and wax emulsions on proximate analysis and some antioxidants of soursop (Annona muricata L.).

The effect of the application of 1-methylcyclopropene (1-MCP) and wax emulsions, alone or combined, on composition analysis, vitamin C, polyphenols, and antioxidant capacity of soursop was evaluated. Fruits were stored as follows: at 25 °C (control), and at 16 °C: fruits sprayed with candelilla or flava emulsions, fruits treated with 1500 nL/L of 1-MCP (20 °C, 12 h), and fruits treated with 1-MCP and then sprayed with emulsions. Fruits were allowed to ripen and the edible part was used for analysis. Only fruits stored at 16 °C without 1-MCP showed visible symptoms of chilling injury. Fruits treated with 1-MCP combined with flava emulsion maintained in greater extent their vitamin C content, dietary fiber, total phenolics content, and antioxidant activity. The combination of 1-MCP and emulsions can be utilized in postharvest handling of soursop because this combination can preserve its nutritional composition and antioxidant activity.

By-product from decoction process of Hibiscus sabdariffa L. calyces as a source of polyphenols and dietary fiber.

BACKGROUND: Dietary fiber (DF) and antioxidant compounds are widely used as functional ingredients. The market in this field is competitive and the search for new types of quality ingredients for the food industry is intensifying. The aim of this study was to evaluate the composition and antioxidant activity of by-products generated during the decoction of calyces of four Mexican Hibiscus sabdariffa L. cultivars ('Criolla', 'China', 'Rosalis' and 'Tecoanapa') in order to assess them as a source of functional ingredients. RESULTS: Some calyx components were partially transferred to the beverage during the decoction process, while most were retained in the decoction residues. These by-products proved to be a good source of DF (407.4-457.0 g kg⁻¹ dry matter) and natural antioxidants (50.7-121.8 µmol Trolox equivalent g⁻¹ dry matter). CONCLUSION: The decoction process extracted some soluble carbohydrates, ash and some extractable polyphenols. The DF content changed in the dried residues, which could be considered as high-DF materials with a high proportion of soluble DF (∼20% of total DF) and considerable antioxidant capacity. These by-products could be used as an antioxidant DF source.