Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Combined hydrothermal pre-treatment and enzymatic hydrolysis of corn fibre: production of ferulic acid extracts and assessment of their antioxidant and antiproliferative propertiesPublication . Valério, Rita; Serra, Ana Teresa; Baixinho, João; Cardeira, Martim; Fernández, Naiara; Bronze, MR; Duarte, Luís C.; Tavares, Maria L.; Crespo, João; Brazinha, CarlaABSTRACT: Ferulic acid may be used as a nutraceutical ingredient or as a substrate to produce bio-vanillin. There is an increasing market demand for ferulic acid obtained from natural sources such as low-cost agro-industrial by-products, due to its potential applications as nutraceutical ingredient and as a substrate to produce biovanillin. This work aims to study ferulic acid recovery from corn fibre (one of the most abundant natural sources of ferulic acid), involving an integrated process of hydrothermal pre-treatment followed by enzymatic hydrolysis. The objective is primarily to produce natural extracts with a maximum ferulic acid recovery yield, but it is also to assess their antioxidant and antiproliferative properties and their cytotoxicity. Different commercial enzyme preparations were tested for release of ferulic acid from corn fibre. The best results were obtained for Ultraflo (R) XL in a concentration of 2 % (W-enzyme preparation/W- dry corn fibre) at a pH of 5 and at 55 degrees C, presenting a recovery yield of esterified ferulic acid of 7.83 +/- 1.35 % (w(recovered ferulic acid)/w(total esterified ferulic acid)), which corresponds to 0.13 +/- 0.02 % (w(ferulic acid)/w (thy corn fibre)). When using a hydrothermal pretreatment at a temperature of 140 degrees C for 40 min, prior to the use of the same enzymatic hydrolysis procedure, the recovery yield of esterified ferulic acid increased to 28.94 +/- 2.40 % (W- recovered ferulic acid/ w(total esterified ferulic acid)), which corresponds to 4.9 +/- 0.3 % (w(ferulic acid)/w(dry corn fibre)). The use of this pre-treatment leads not only to the highest yield of ferulic acid, but also to the lowest concentration of furfural and hydroxymethylfurfural, without the formation of formic and levulinic acid (not detected). All pre-treatments tested led to an improved quality of the extract in terms of bioactivity.
- Nanofiltration and reverse osmosis as a platform for production of natural botanic extracts: the case study of carob by-productsPublication . Almanasrah, Mohammad; Brazinha, Carla; Kallioinen, Mari; Duarte, Luís C.; Roseiro, Luisa B.; Lukasik, Rafal M.; Carvalheiro, Florbela; Manttari, Mika; Crespo, JoãoCarob kibbles are a low-cost and renewable source of economically relevant phenolic compounds (high value catechin and its derivatives and gallic acid) and abundant in small sugars. This work aims at producing two distinct natural extracts from carob kibbles, one extract enriched in catechin and its derivatives for the nutraceuticals market and an extract enriched in sugars for the food industry. This valorisation strategy involves an integrated process based on membrane technology that fulfils the zero discharge principle and may be applied to other agro-industrial by-products. Different aqueous extraction schemes were considered (a one-step process and a two-steps approach). The aqueous extracts obtained were fractionated by diananofiltration and the fractions obtained were evaluated in terms of their content in target products. An integrated scheme for production of fractionated extracts is proposed based on the experimental work developed assuring, simultaneously, a minimal use of resources and emission of waste.
- Selective recovery of phenolic compounds and carbohydrates from carob kibbles using water-based extractionPublication . Almanasrah, Mohammad; Roseiro, Luisa B.; Lukasik, Rafal M.; Carvalheiro, Florbela; Brazinha, Carla; Crespo, João; Kallioinen, Mari; Manttari, Mika; Duarte, Luís C.Carob kibbles are an important renewable source of valuable compounds, such as fermentable sugars and phenolic compounds. However, the selective recovery of these compounds is not a trivial task. In this work, a strategy was developed to enable the recovery of both classes of compounds by means of awater-based extraction.One-step extraction recovered only approximately 20% of the phenolic compounds, corresponding to an extraction yield of 0.6 g Gallic acid equivalents (GAE)/100 g dry mass of carob kibbles. The obtained extract contained a significant amount of carbohydrates (110 g/L). The alternative two-step extraction developed enabled higher compound selectivity together with an increase in the yield of the phenolic compounds to about 70%, corresponding to 1.9 gGAE/100 g carob dry matter.The two-step extraction was easily scaled-up and is an effective method to obtain significantly sepa-rated carbohydrates and polyphenol-rich streams that can be further processed, e.g., in biorefineries orfood industries, respectively.