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The skimmed goat milk was submitted to the nanofiltration process using a volume reduction factor (VRF) equal to 2. It was verified a rapid decrease of the permeate flux at a low time, with a continuous flux, caused by the reversible resistance, which is characterized by the standard and complete blocking. The combined fouling model was evaluated, including complete pore blocking and cake filtration mechanism, which described the skimmed goat milk nanofiltration behavior. For the VRF equal to 2 was determined the total solids, protein, lactose, ash, mineral fraction content, which increased successfully with the nanofiltration process. The Power Law and Herschel-Buckley models were fitting to describe the flow behavior for retentate, which presented the higher apparent viscosity. Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Xanthohumol, a chalcone unique to hops, has attracted attention from researchers due to its several pharmacological effects on humans. In industry, hops are almost exclusively used in beer production, generating tons of solid waste - hot trub from the boiling step and spent hops from the dry hopping - rich in biocompounds, among them xanthohumol, that could be recovered and used for several nutritional purposes. The literature is extensive on extraction processes of xanthohumol directly from hops, but only a few studies present its recovery from brewery solid waste. We focus on presenting the xanthohumol characteristics and benefits for human consumption, and discuss the main extraction techniques, their advantages and limitations, to prospect strategies to recover this high-value compound from brewing solid waste. Recent extraction processes represent promising approaches to overcome the limitations of conventional methods, but further studies are still needed to understand xanthohumol extraction and purification and induce industrial upscaling.

The aim of this study was to evaluate the microfiltration and nanofiltration of strawberry juice. Processes performance was evaluated in terms of resistances-in-series, flux decline modeling and extract quality (maintenance of the phenolic compounds). The results obtained showed that concentration polarization is the main resistance to permeate flux in nanofiltration process, representing around 95% of the total resistance. Microfiltration process suffered more influence of the concentration polarization and fouling, next to 47% for both resistances. For all the processes, Hermia’s pore blocking models presented good fitting, with R(2) over 0.85. The same behavior was observed for a conjugated model which provided a realistic description (R(2) > 0.76). Also, nanofiltration process allowed phenolic compounds maintenance, demonstrating the efficiency of this process for strawberry juice concentration.

This study aimed to recover bioactive compounds from by-product of acerola processing. Firstly, hydrothermal treatment was carried out to extract the compounds, and later, it was concentrated by nanofiltration (NF). Central Composite Rotational Design associated with response surface methodology was applied to maximize the extraction. The optimal conditions were 15 min and a liquid-solid ratio of 22 mL/g (water/non-pomace). The optimized extract was concentrated in NF by a volumetric factor of 13-fold to provide a concentrated product with characteristics compatible with acerola juice. The concentration resulted in the following retentions (R%) and concentration factors (CF): 94.9% and 9.2 for total phenolic content (TPC), 91.6% and 4.9 for ascorbic acid (AA), 99.0% and 8.0 for antioxidant compounds, respectively. NF membrane also showed retention higher than 90.0% for catechin, caffeic acid, ferulic acid, and rutin. TPC and antioxidant activity found in the concentrated extract was 1.3 and 1.5-fold higher than the acerola juice, respectively. The AA content in the extract was below the value found in the juice, 7.9 and 9.1 mg/mL, respectively. Finally, the hydrothermal treatment resulted in higher extraction of phenolic compounds compared to conventional extraction, and its integration with NF resulted in a high content of bioactive compounds., The authors are grateful to CAPES-PRINT project number 88887.310560/2018-00472 and DINTER/CAPES 1955/2016 process number 23038.021515/2016-97.

Strawberry juice was concentrated using block freeze concentration process. The concentrate was used to produce two yogurts with different concentrations of cryoconcentrated strawberry pulp (15% and 30%). Total lactic acid bacteria count, physicochemical and rheological properties was evaluated during storage (7days) for all yogurts. Also, the beverages produced were compared with two commercial trademarks. It was observed that the total lactic acid bacteria count remained higher than 108CFU·mL-1 during the storage time for all beverages studied. The viscosity of the yogurts decreased when the ratio of strawberry cryoconcentrate was increased. The Power Law model was successfully applied to describe the flow of the yogurts, which had a thixotropic behaviour. The incorporation of the cryoconcentrated strawberry pulp in the yogurt resulted in a product with 3-fold more anthocyanins content and antioxidant activity. The enrichment of natural yogurt with strawberry cryoconcentrated pulp proved to be effective in the production of a beverage with higher nutritional characteristics.

•The potential of strawberry juice as a source of bioactive compounds.•Nanofiltration performance for phenolic compounds concentration.•Strawberry juice antioxidant activity increased after nanofiltration process.•Antioxidant activity of the concentrate juice was correlated with anthocyanins.

Summary The aim of this study was to evaluate the effects of freeze concentration of strawberry juice on content of total phenolic, anthocyanins content and antioxidant activity of the concentrated fluid and the ice obtained. An increase in the values of phenolic content was observed in the concentrate fraction for all the freeze concentration stages (five stages). The process efficiency presented a reduction when compared with the first stage, and however, the average efficiency remained around 65% in all the stages. The concentration of pelargonidin-3-O-glycoside present in samples was increased in all stages. Furthermore, the antioxidant activity of the concentrated fluid of each stage, measured by DPPH and ABTS methods, was significantly higher in comparison with the juice feed. Also, antioxidant activity can be correlated with the content of pelargonidin-3-O-glycoside presented in the strawberry juice. Freeze concentration can be considered a good alternative for improving the antioxidant activity of strawberry juice.

In this paper the physicochemical characteristics and the flow decline occurring during the reverse osmosis of skim milk, were analysed. The flow decline was evaluated using the resistances in series, the blocked pore models and a second conjugated model that combined the blocked pores with the development of a filter cake. The main resistance found was the concentration by polarization, which was mainly influenced by the complete blocking of the pores. The conjugated model was capable of predicting the flow decline of the process. With respect to the physicochemical properties, more than 98% of the lactose, protein, oils and fats were retained, demonstrating the efficiency of the process. Resumo Neste trabalho, as características físico-químicas e o declínio de fluxo durante o processo de osmose inversa foram analisados. O declínio de fluxo foi avaliado utilizando-se resistências em série, os modelos de bloqueio de poro e um segundo modelo conjugado, que consiste na combinação de resistências decorrentes dos bloqueios de poro e do desenvolvimento da torta de filtração. A principal resistência encontrada foi a concentração por polarização, sendo que o processo foi principalmente influenciado pelo bloqueio completo de poros. O modelo conjugado foi capaz de predizer o declínio de fluxo do processo. Em relação às propriedades físico-químicas, a lactose, a proteína e os óleos e gorduras apresentaram uma retenção acima de 98%, demonstrando a eficiência do processo.