Lourdes M.C. Cabral

Microfiltration and reverse osmosis for clarification and concentration of acerola juice

Abstract The exotic tropical fruits are adequate for the increasing market of fruit juices and based fruit drinks by their diversity of aromas and flavours and by their nutritional value. In such group, acerola appears as potentially attractive due to its high ascorbic acid content. The objective of this work was to develop a process for obtaining clarified and concentrated acerola juice, maintaining its nutritional and sensory characteristics. The experimental procedure consisted of fruits pulping followed by an enzymatic hydrolysis, a clarification by microfiltration and the concentration by reverse osmosis. The obtained products presented the required microbiological counts and nutritional quality due to the ascorbic acid preservation. Vitamin C content of the integral juice was 1234 mg/100 g and in concentrated juice it reached 5229 mg/100 g. In an acceptability test most of the consumers (84%) liked the drink prepared with the clarified juice.

Effect of enzymatic treatment and filtration on sensory characteristics and physical stability of soymilk

Abstract Several hydrolytic enzymes––Celluclast 1.5L, Pectinex ultra sp, Rohalases (SEP, F, 7069 e 7118)––and filtration with different pore size tissues––20; 30; 85; 100 μm––were independently studied, regarding their effect on the sensory quality of whole soymilk. The whole soymilk process included the following operations: dehulling, boiling, draining, grinding, homogenisation, enzymatic treatment or filtration, and heat treatment. The treatment with Celluclast 1.5L or filtration using a 20-μm tissue resulted in a considerable reduction of the particle size suspended in the soymilk. Such reduction originated products with low levels of sensory attribute of chalkiness and higher physical stability, in comparison to the control submitted to either one or two homogenisations. The enzymatically treated soymilk resulted in a higher global impression of flavour than the filtered product and the products submitted to one and two homogenisations, respectively.

Membrane for processing tropical fruit juice

In the present work, membrane processing was investigated in order to clarify and to recover aroma from tropical fruit juices. Pineapple and passion fruit juices were selected. Pervaporation experiments were also carried out with binary synthetic aqueous solutions of typical aroma components. Experimental and simulation results indicated that olefin pervaporation membranes presented a good performance due to its low water permeability and high enrichment factor to the components of aroma from the investigated synthetic solutions, as well as the single strength and the clarified fruit juices.

Clarificação e concentração de suco de caju por processos com membranas

Os processos de separacao por membranas tem sido estudados como alternativa aos processos termicos de conservacao de alimentos, por serem conduzidos em condicoes amenas de temperatura, permitindo, assim, a preservacao de compostos termosensiveis como as vitaminas, por exemplo. O objetivo deste trabalho foi avaliar a utilizacao da microfiltracao e da osmose inversa para a obtencao de suco de caju clarificado e concentrado. O processamento consistiu de tres etapas principais: o tratamento enzimatico do suco integral; a microfiltracao para obtencao do suco clarificado; e a concentracao do suco clarificado por osmose inversa. Para o tratamento enzimatico, utilizou-se um complexo pectinolitico durante 1 hora. A clarificacao foi conduzida em uma unidade de microfiltracao tubular e, em seguida, foi utilizado um sistema de osmose inversa, do tipo quadro e placas, para concentrar o suco clarificado. Os fluxos medios de permeado obtidos foram de 184,0 e 11,3L/hm2 para a microfiltracao e a osmose inversa, respectivamente. Os taninos, responsaveis pela adstringencia do suco, foram retidos pela membrana de microfiltracao e, por isso, nao foram detectados nos sucos clarificado e concentrado. O suco clarificado contendo 12,1° Brix foi concentrado ate 28,6° Brix. A vitamina C aumentou de 162mg/100g no suco clarificado para 372mg/100g, no concentrado.

Antioxidant dietary fibre recovery from Brazilian Pinot noir grape pomace

Brazilian grape pomace was extracted in hot water, and a factorial experiment was used to evaluate polysaccharide recovery. The dependent variables were the temperature, particle size and solute:solvent ratio. Polysaccharide yields varied from 3% to 10%, and the highest sugar content was observed when extraction was carried out at 100 °C from finely sized particles (⩽249 μm) in a 1:12 solute:solvent ratio. The monosaccharide composition of extracts obtained from flours were, on average, Rha:Ara:Xyl:Man:Gal:Glc:GalA in a 3:32:2:13:11:20:19 M ratio, with varying Glc:GalA ratios. (13)C NMR and HSQC spectra confirmed the presence of pectic- and glucose-based polysaccharides in the extracts. Phenolic compounds were found after pomace extraction, and catechin, gallic acid and epicatechin were the principal compounds identified. The extracts also had ABTS radical scavenging capacity (from 8.00 to 46.60 mMol Trolox/100 g pomace). These findings indicate that these grape pomace flours are rich in antioxidant dietary fibre and have a potential use as food ingredients.

Addition of grape pomace extract to probiotic fermented goat milk: the effect on phenolic content, probiotic viability and sensory acceptability.

BACKGROUND Grape pomace is a source of phenolic compounds, which are associated with health benefits in humans. Additionally, fermented dairy foods with probiotics can be good vehicles to deliver these bioactive compounds. The effects of the addition of grape pomace extract (GPE) on the total phenolic (TP) content, physico-chemical characteristics and viability of Lactobacillus acidophilus LA-5 or Lactobacillus rhamnosus HN001 in fermented goat milks prepared with grape juice were investigated. RESULTS The TP concentration increased significantly in fermented milks with the addition of GPE. A protective effect of GPE on the viability of L. acidophilus was observed. However, after 14 days of storage, the populations of L. acidophilus were significantly lower when compared with those of L. rhamnosus, and only the last probiotic maintained its viability above 7 log CFU mL-1 throughout the period investigated. The sensory scores of flavor, color and overall acceptability of the fermented milk containing L. rhamnosus HN001 were significantly increased when GPE was added. CONCLUSION The use of GPE might increase the functionality of probiotic fermented goat milk processed with L. rhamnosus HN001 and grape juice because grape polyphenols are known for their antioxidant properties and positive effect on the modulation of gut microbiota.

Towards integral utilization of grape pomace from winemaking process: A review

Grape is the main fruit crop in several countries. Although many grape-based food products can be found in the market, studies have shown that around 75% of the world grape production is destined for the wine industry. Grape pomace is an abundant by-product from the wine industry, which consists of the remaining skin, seeds and stalks and represents around 25% of total grape weight used in the winemaking process. In countries such as Italy, France and Spain, where wine production is more relevant, the annual grape pomace generation can reach nearly 1200 tonnes per year. In order to reach a sustainable winemaking process there is a need of a waste reduction policy. Several studies explore this subject using grape pomace as a source of healthy and technological compounds that could be applied in animal feed, pharmaceutical, cosmetic or food industry to improve stability and nutritional characteristics, and in cosmetic industry, where grape seeds oil is widely used. This review aims to approach the recent winemaking scenario and the benefits achieved when a waste management policy is implemented, as well as to compare available extractive technologies and a wide alternative of uses for grape pomace.

Grape by-product extracts against microbial proliferation and lipid oxidation: a review.

The wine industry is responsible for the production of million tons of waste, such as grape skin, stalk, sludge and seeds, which can be considered inexpensive sources of phenolic compound owing to incomplete extraction during wine production. Phenolic compounds, also called polyphenols, comprise the most abundant bioactive compounds in grape and are recognized by their antioxidant and antimicrobial potential. Because of their functional properties, extracts obtained from grape wastes, which are rich in phenolic compounds, can be employed in the development of many products, ranging from medical to food applications, decreasing the growth of spoilage and pathogenic microorganisms and inhibiting lipid oxidation. These characteristics are motivating the research for alternative sources of natural antioxidant and antimicrobial agents, aimed at decreasing the use of artificial additives, which have been associated with some toxic effects. This article provides a review of the use of grape by-product extracts and their bioactive compounds as natural antioxidant and antimicrobial agents in food products.

Coupling of ultrafiltration and enzymatic hydrolysis aiming at valorizing shrimp wastewater.

The objective of this work was to obtain a protein hydrolysate from the wastewater generated during shrimp cooking, by coupling ultrafiltration and enzymatic hydrolysis processes. Initially, the effluent was concentrated by ultrafiltration, reaching a protein concentration factor of 3.2. The concentrated effluent was then enzymatically hydrolyzed, aiming at obtaining peptides with antioxidant capacity. The effects of some process variables--temperature (55-75 °C), pH (7-9) and enzyme/substrate (E/S) ratio (0.1-2.5%)--on the degree of hydrolysis and the antioxidant capacity were evaluated. The increase in temperature and pH resulted in lower degree of hydrolysis and higher antioxidant capacity. The conditions selected as the most suitable were: temperature of 75 °C, pH of 9.0 and E/S ratio of 0.1%. The hydrolysates produced at these conditions were also evaluated for total amino acid content and electrophoretic profile, showing a suitable amount of essential amino acids that covers the recommended daily needs.

Cellulose nanocrystals from grape pomace: production, properties and cytotoxicity assessment

Cellulose nanocrystals (CNCs) were obtained from grape pomace through chemical and physical pretreatments. Bleached cellulose pulp was subjected to acid hydrolysis (AH) for 30 or 60 min and an ultrasound treatment to obtain CNCs (AH30S and AH60S). Compositional analyses of untreated (UGP) and pretreated (PGP) grape pomace showed the effectiveness of pretreatment in removing non-cellulosic components, recovering 80.1% cellulose in PGP (compared to 19.3% of UGP). Scanning and transmission electron microscopies were used to evaluate the CNCs morphology. AH in combination with ultrasound treatment led to needle-shaped structures and apparently more dispersed suspensions. Crystallinity index and thermal stability were studied by X-ray diffraction and thermogravimetric analysis, respectively. The AH60S sample presented high aspect ratio, crystallinity and thermal stability. CNCs toxicity was evaluated by exposing Caco-2 cells to CNCs suspension and evaluating their viability. Results showed that CNCs are non-toxic, opening the opportunity for their use on food and pharmaceutical applications.