Dehydration of acerola ( Malpighia emarginata D.C.) residue in a new designed rotary dryer: Effect of process variables on main bioactive compounds

Acerola processing waste: Convective drying with ethanol as pretreatment

The acerola seed is an agro-industrial waste. It is a high moisture content product, rich in bioactive compounds. Drying is an alternative to make this waste available in a safe condition. The use of ethanol as a pretreatment could improve the drying process besides reducing the operation time. This study aimed to investigate the influence of ethanol pretreatment (ET) on the content of bioactive compounds, cell wall thickness, and color. The drying kinetics was studied, and the influence of external and internal resistance was discussed. The samples were immersed in ethanol for 2 min with subsequent convective drying (40 °C and 60 °C; 1 m s-1) until they reached the equilibrium condition. The ET reduced the drying time up to 36.36 %. The external and mixed control of mass transfer were identified as the governing regimes for drying this material, depending on the use of ethanol. ET led to an increase in effective diffusivity, a reduction in cell wall thickness, and preservation of the color of the dried waste. The ET positively impacted the conservation of ascorbic acid compared to untreated dried samples but was not relevant to phenolic compounds, carotenoids, and antioxidant activity. The drying process increased the bioactivity of the anthocyanins. The best condition was drying at 60 °C, pretreated with ethanol.

Application on infrared spectroscopy for the analysis of total phenolic compounds in fruits

Recent studies have demonstrated the metabolic benefits of phenolic compounds on human health. However, traditional analytical methods used for quantification of total phenolic compounds are time-consuming, laborious, require a high volume of reagents, mostly toxic substances, and involve several steps that can result in systematic and instrumental errors. Spectroscopic techniques have been used as alternatives to these methods for the determination of bioactive compounds directly in the food matrix by minimal sample preparation, without using toxic reagents. Therefore, this overview presents the advantages of nondestructive methods focusing on infrared spectroscopy (IR), for the quantification of total phenolic compounds in fruits. In addition, the main difficulties in applying these spectroscopic techniques are presented, as well as a comparison between the quantification of total phenolic compounds by traditional and IR methods. This review concludes by focusing on model building, highlighting that IR data are mainly processed using the partial least-squares (PLS) regression method to predict total phenolic content. The development of portable and inexpensive IR instruments, combined with multivariate data processing, could give to the consumers a straightforward technology to evaluate the total phenolic content of fruits prior to purchase.

Bioactive compounds and antioxidant activities in the agro-industrial residues of acerola (Malpighia emarginata L.), guava (Psidium guajava L.), genipap (Genipa americana L.) and umbu (Spondias tuberosa L.) fruits assisted by ultrasonic or shaker extraction

The aim of this study was to analyze the residue powders of Malpighia emarginata L., Psidium guajava L., Genipa americana L. and Spondias tuberosa L. regarding their total phenolic compounds contents, antioxidant activity (ABTS, DPPH and FRAP), soluble sugars, carotenoids, organic acids by HPLC-DAD/RID and individual phenolic compounds by the UPLC-QDa-MS system. The genipap residue had a high content of soluble sugars (422.72 ± 19.15 mg.g^-1 DW), with a higher content of sucrose (170.83 ± 10.89 mg.g^-1 DW). Nystose was found in the residues of guava (6.59 ± 0.56 mg.g^-1 DW) and umbu (65.61 ± 2.31 mg.g^-1 DW). The residues of acerola and umbu showed contents of β-carotene of 5.84 ± 0.01 mg.g^-1 DW and 0.10 ± 0.05 mg.g^-1 DW, respectively while high concentration (1116.00 ± 2.00 mg.100 g^-1 DW) of tartaric acid was found in acerola residue and quinic acid (6340 ± 104.00 mg.100 g^-1 DW) in umbu residue. Acetone (80%) and ultrasonic extraction were the best conditions for the residues of acerola, guava and genipap, however, for the umbu residue, extraction with shaker showed better results. The acerola and umbu residues showed higher yields of total phenolics, the values being 378.69-444.05 mg GAE.100 g^-1 DW and 326.14-404.36 mg GAE.100 g^-1 DW, respectively, as well as antioxidant activity. Naringenin was the individual phenolic compound with the highest concentration in the residue of acerola and genipap, vanillin in guava and rutin in umbu. Thus, residues powders from acerola, guava, genipap and umbu constitute potential sources of bioactive compounds, which could be used in the food, pharmaceutical and cosmetic industries.

Optimization of ultrasound-assisted extraction of bioactive compounds from acerola waste

The industrial processing of acerola (Malpighia emarginata D.C.) produces huge quantities of waste material that are badly discarded or undervalued. In spite of this, acerola wastes have a high content of antioxidant compounds. The aim of this work was to study the extraction of antioxidant compounds from acerola residues using ultrasound assisted extraction. Using multiple regression techniques, the effects of ethanol concentration in the hydroethanolic solution (C), extraction time (t), temperature (T), and liquid-solid ratio (R) on the total phenolic content, total flavonoid content and antioxidant potential were investigated. The best extraction conditions were identified using the desirability function, which is a multi-response optimization technique. The optimal processing parameters were 67.5% of ethanol concentration, temperature of 80.9 °C, liquid/solid ratio of 59.8 mL/g, and extraction time of 13.6 min. HPLC-UV has been used to identify the main antioxidant compounds obtained under these optimal condition. Based on the results, acerola waste has high potential for better use, such as in food and pharmaceutical applications.

Acerola fruit as a natural antioxidant ingredient for gluten-free bread: An approach to improve bread quality

In this study, we evaluated the effect of enrichment of bread using acerola fruit powder on the physical, sensorial and antioxidant properties of gluten-free breads. We tested different proportions of acerola fruit powder (0-5% w/w) in rice flour. According to the results, loaf volume increased from 423.33 cm³ to 571.67 cm with increasing amount of acerola fruit powder cm³ with increasing amount of acerola fruit powder (from 0 to 5% w/w). Acerola fruit powder improved the structural parameters of the crumb by increasing the size and area fraction of cells. All tested quantities of acerola fruit powder improved textural parameters by decreasing firmness and chewiness and by increasing springiness. In addition, acerola fruit powder positively affected the antioxidant properties of enriched breads. The total phenolic content and antioxidant activity of extracts was found to be increased with the addition of acerola fruit powder. All antioxidant activities were found to be increased with increasing quantities of acerola fruit powder. The sensory attributes of the bread showed that a partial replacement of the rice flour with up to 3% of acerola fruit powder provided satisfactory results. The optimum level of acerola fruit powder for all parameters tested was found to be 3% w/w.

Vitamin C stability in acerola and camu-camu powder obtained by spray drying

Abstract Acerola and camu-camu fruits possess high vitamin C content. However, since these fruits are little consumed in their fresh form, it is important to consider that vitamin C can be oxidized depending on storage conditions. Thus, this study aimed to produce acerola and camu-camu powders by spray drying to maintain the stability of their vitamin C content during storage. Acerola and camu-camu powders were characterized in relation to their physicochemical characteristics, antioxidant activity, and vitamin C concentration and stability under different storage conditions (30 °C and 40 °C, 75% relative humidity). In general, the powders were proven to be stable, with low water activity (< 0.40) and humidity (< 4.0 g/100 g powder), as well as high vitamin C concentrations (1593.2 and 6690.4 mg/100 g of powder for acerola and camu-camu, respectively). Furthermore, we observed a high antioxidant activity by ABTS●+, DPPH• and FRAP assays. The powders stored at lower temperature (30 °C) showed higher vitamin C stability. In conclusion, acerola and camu-camu powders produced by spray drying are potential sources of vitamin C and active compounds and are therefore suitable for several food industry applications.

Graviola Fruit Bar Added Acerola By-Product Extract Protects Against Inflammation and Nociception in Adult Zebrafish (Danio rerio)

Studies involving foods associated with pain reversal and anti-inflammatory effects using zebrafish are rarely reported in the literature. This study aimed to evaluate the effect of graviola (Annona muricata L.) fruit bar (GFB) and GFB added with acerola (Malpighia glabra L) seed extract (ASE) on acute nociception and abdominal inflammation in adult zebrafish (Danio rerio). Acute nociception was induced by formalin, capsaicin, cinnamaldehyde, acidic saline, glutamate (cutaneous models), and hypertonic saline (corneal model), and inflammation was induced by carrageenan. Both GFB and ASE exhibited antinociceptive effect modulated by the nitrergic system, guanylate cyclase, and transient receptor potential ankyrin 1 and acid-sensing ion channels. The antinociceptive effect of GFB also appears to be modulated by the opioid system and glutamatergic receptors (N-methyl-D-aspartate receptor). Only ASE presented corneal antinociceptive effect. Both samples showed anti-inflammatory effect, being more significant the effect of GFB. The addition of acerola by-product extract in GFB results in a product with greater biological potential.

Hydrothermal carbonization of acerola (Malphigia emarginata D.C.) wastes and its application as an adsorbent

Hydrothermal carbonization (HTC) is a promising technique for the improved management and better use of agro-industrial wastes. In this study, the effects of temperature, reaction time, biomass/water ratio, feed-water pH, and agitation speed on the HTC of acerola wastes were investigated. The effects of these independent variables on process yield and on the total oxygenated functional groups of hydrochars were quantified. The best process conditions were obtained using the desirability function and the chemical-morphological properties of the hydrochar produced in these optimal conditions were investigated. The total number of oxygenated functional groups were found to be higher than those described in the literature for similar biomasses. The effects of temperature, solution pH, initial dye concentration, and adsorbent dosage on the adsorption of methylene blue using the obtained hydrochar were also investigated and the conditions necessary for the maximum removal and adsorption capacity were determined. Adsorption isotherms and thermodynamic studies have shown that methylene blue adsorption on the obtained hydrochar is endothermic and spontaneous. Thus, the HTC of acerola wastes may be a sustainable technology for the modification of underutilized wastes and their application as adsorbents of environmental contaminants.

Impact of combining acerola by-product with a probiotic strain on a gut microbiome model

In this study, we first investigated the survival of three probiotic strains, individually and combined with acerola by-product during simulated gastrointestinal conditions. Next, we investigated the effects of acerola by-product combined with Bifidobacterium longum BB-46 on a gut microbiota model (SHIME®). Chemical composition, total phenolic compounds, antioxidant activity of the acerola by-product and microbial counts, denaturing gradient gel electrophoresis (DGGE), ammonium ions ( NH4+ ) and short-chain fatty acids (SCFAs) analysis of the SHIME® samples were performed. Acerola by-product revealed high protein and fibre, reduced lipid contents, and showed to be an excellent source of total phenolic compounds with high in vitro antioxidant activity. A decreased amount of NH4+ in the ascending colon and an increase (p < .05) in SCFAs were observed in the three regions of colon during treatment with BB-46 and acerola by-product. BB-46 combined with acerola by-product showed positive effects on the gut microbiota metabolism in SHIME® model.

Heavy metals uptake on Malpighia emarginata D.C. seed fiber microparticles: Physicochemical characterization, modeling and application in landfill leachate

Environmental heavy-metals contamination is a worldwide concern and the treatment of their sources constitutes a sustainable and efficient alternative. This work investigated the performance of Malpighia emarginataD.C. seed fibers microparticles (Me-SFMp) as biosorption platform for heavy metal ions. Integrated physicochemical analyses (FAAS, FTIR, SEM/EDS and XRF) showed that such ability was associated with the high microstructural porosity, wide surface area and diversity of functional groups on Me-SFMp structures, which favored the high and fast uptake of the target-substances (Cd, Zn, Cr, Pb, Cu and Ni ions). In terms of reactional kinetics, the pseudo-second order model showed better data correlation (R² from 0.9992 to 0.9998) and suggested the chemisorption as limiting step of the reaction mechanisms. From the Langmuir isotherms (R² from 0.9993 to 0.9998), it was observed that these phenomena occurred non-linearly on a homogeneous biosorbent monolayer. Me-SFMp can also be reused after desorption processes conducted in acid medium and, under ideal conditions (0.8 g biosorbent dosage; 100 mL of 1.00 mg L^-1 multi-metal solution adjusted to pH = 8.0; 300 rpm stirring speed; and 60 min contact time), the following maximum removal percentages order was observed for the first cycle: Cd (100%) = Zn (100%) > Cr (95.1%) > Pb (86.8%) > Cu (84.2%) > Ni (81.0%). The procedure was successfully applied to remove the studied heavy metal ions from raw landfill leachate, even in the presence of several (in)organic interferers, reinforcing the strong biosorbent-adsorbate interaction and the viability of this proposal.

Microencapsulation and the Characterization of Polyherbal Formulation (PHF) Rich in Natural Polyphenolic Compounds

Microencapsulation of polyherbal formulation (PHF) extract was carried out by freeze drying method, by employing gum arabic (GA), gelatin (GE), and maltodextrin (MD) with their designated different combinations as encapsulating wall materials. Antioxidant components (i.e., total phenolic contents (TPC), total flavonoids contents (TFC), and total condensed tannins (TCT)), antioxidant activity (i.e., DPPH, β-carotene & ABTS⁺ assays), moisture contents, water activity (aw), solubility, hygroscopicity, glass transition temperature (Tg), particle size, morphology, in vitroα-amylase and α-glucosidase inhibition and bioavailability ratios of the powders were investigated. Amongst all encapsulated products, TB (5% GA & 5% MD) and TC (10% GA) have proven to be the best treatments with respect to the highest preservation of antioxidant components. These treatments also exhibited higher antioxidant potential by DPPH and β-carotene assays and noteworthy for an ABTS⁺ assays. Moreover, the aforesaid treatments also demonstrated lower moisture content, aw, particle size and higher solubility, hygroscopicity and glass transition temperature (Tg). All freeze dried samples showed irregular (asymmetrical) microcrystalline structures. Furthermore, TB and TC also illustrated the highest in vitro anti-diabetic potential due to great potency for inhibiting α-amylase and α-glucosidase activities. In the perspective of bioavailability, TA, TB and TC demonstrated the excellent bioavailability ratios (%). Furthermore, the photochemical profiling of ethanolic extract of PHF was also revealed to find out the bioactive compounds.

Effects of dehydration methods on quality characteristics of yellow passion fruit co-products

BACKGROUND

The production and processing of fruits generate a large amount of residues, which are usually disposed of or under-used, representing losses of raw material and energy. The present paper investigates the effect of four dehydration techniques (convective, infrared, microwave and freeze-drying) on yellow passion fruit (Passiflora edulis f. flavicarpa) co-products and the influence of the main variables on moisture removal and bioactive compounds. The compounds analyzed were total phenolics, total flavonoids, ascorbic acid and pectin.

RESULTS

The content of phenolics and flavonoids increased after dehydration in all techniques investigated and the process temperatures directly affected the ascorbic acid content. Microwave dehydration showed the best results for most bioactive compounds analyzed, if performed in suitable process conditions. However, the highest levels of pectin content were obtained by freeze-drying and convective dehydration.

CONCLUSION

This study reinforces the importance of the adequate use of passion fruit co-products due to the high levels of bioactive compounds in this material. Microwave dehydration presented the best results, which indicates the potential use of this technique for a better exploitation of fruit co-products. Larger quantities of pectin were extracted from samples dehydrated through methodologies with long-time process and low temperatures, such as convective drying and freeze-drying. © 2017 Society of Chemical Industry.