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Valorization of spent brewer's yeast: optimization of hydrolysis process towards the generation of stable ACE-inhibitory peptides

Publication . Amorim, Manuela; Pinheiro, Hélder; Pintado, Manuela

Establishing of a bio-based and green society makes it possible to take actions to exploit high value resources that can be converted into valuable biological ingredients. Brewer's spent yeast is a natural byproduct from the brewing industry with high biological and nutritional richness. In the present research, the effect of autolysis and subsequent hydrolysis of spent brewer's yeast, using an extract of Cynara carduncuius was investigated by response surface methodology, to define the optimal conditions with maximized angiotensin converting enzyme inhibitory activity (ACE-I). The models describe maximum autolysis obtained at 70 degrees C for 5 h followed by hydrolysis at 4% (v/v) E/S ratio for 4.5 h, where the peptide extract obtained had IC50 of 146 mu g mL(-1) of protein content. Nanofiltration allowed to produce a fraction with < 3 kDa exhibiting highest inhibitory activity (IC50 84.2 mu g mL(-1)) and showed to be stable in vitro gastrointestinal system maintaining its activity. The results suggest an alternative use of brewer's byproduct as source of beneficial ingredient in the prevention and/or treatment of hypertension, where the protein hydrolysis improves ACE-I activity.

2019Journal article

Restricted access

Effects of whey peptide extract on the growth of probiotics and gut microbiota

Publication . Yu, Ya-Ju; Amorim, Manuela; Marques, Cláudia; Calhau, Conceição; Pintado, M. E.

Whey peptide extract with molecular weight below 1 kDa was investigated in microplate assay, and viable cells, as well as metabolic activity were determined to evaluate augmented growth of probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium animalis). Results illustrated that whey peptide extract 1% (w/v) has the capacity to stimulate the proliferation of both probiotic bacteria tested, further supported by the faster generation of metabolic products. The effect of whey peptide extract on the modulation of gut microbiota was also examined inWistar rats fed either with a standard or a high-fat diet, assessed via 16S ribosomal RNA expression of gut microbiota by quantitative PCR. Relative abundance of Lactobacillus spp., Bifidobacterium spp. and Bacteroidetes was significantly increased by whey peptide extract in rats fed with a standard diet. These results highlight an additional unexploited positive effect of whey peptide extract on gut microbiota modulation.

2016Journal article

Restricted access

Use of whey peptide fraction in coated cashew nut as functional ingredient and salt replacer

Publication . Amorim, M.; Pereira, J. O.; Silva, L. B.; Ormenese, R. C. S. C.; Pacheco, M. T. B.; Pintado, M.

Consumers are increasingly concerned about healthy eating habits. The incorporation and stability of 2% antihypertensive whey peptide extract in a new coating of cashew nuts with reduced salt (less 15 and 30%) was studied. The evaluation of nutritional value, in vitro antihypertensive activity and consumer acceptance of final products was assessed. Incorporation of peptide fraction assured the production of a snack with an ACE-inhibitory activity (532.2 μgmL−1 IC50 value). The amount of lipids present in coated cashew nuts was composed mainly by essential fatty acids, mostly monounsaturated. Glutamic acid, leucine, arginine and aspartic acid were the most abundant essential aminoacids. 70% of the consumers considered both samples (15 and 30%) as “ideal taste”. The results suggest that the new coating allowed the development of a new snack with reduced salt content, opening new opportunities as carrier of other ingredients to develop more diversified and efficient functional foods.

2018Journal article

Restricted access

Formulation and consumer acceptance of cereal bars with functional properties by the incorporation of peptides and β- glucans from Spent Brewer's Yeast

Publication . Amorim, Manuela; Pereira, Joana; Pinheiro, Hélder; Pacheco, Maria Teresa; Pintado, Manuela

The market for functional ingredients and foods has a high growth due to increased awareness and promotion of healthy eating and lifestyle of consumers. Food can be used as vehicle to intake bioactive compounds that provide health benefits and increase people well-being. Thus, cereal bars are a popular and convenient food, which is an ideal carrier to incorporate functional ingredients that promote health and prevent diseases. The design and development of functional foods should not be made based solely on nutritional function without taking into account product properties, such as color, texture, flavor and taste. The sensory properties are the most important attributes for the consumer acceptance, as well as other quality issues such as stability and texture. This work was focused on the formulation and sensory analysis of cereal bars obtained by incorporation of peptides and β-glucans extract obtained via autolysis and hydrolysis of spent brewer’s and presenting biological activities such as, antihypertensive and prebiotic. However, this ingredient results in particular taste and flavor that may constrain the matrix choice and consumer acceptance. The cereal bar was formulated based on oat, rice and corn and added 2% extract. Consumer acceptance tests were performed to test general acceptability in particular for the appearance, aroma, flavor and texture by hedonic scale of nine points (9 = liked a lot and 1 = dislike very much) and intent to purchase of 5 point scale (5= definitely would buy and 1= definitely would not buy). The final cereals bars were assessed by 52 consumers and showed positive response since "like" for all attributes were obtained. Regarding the intention to purchase, the sample had an average between "maybe bought" and "probably would buy". So these results suggest that cereal bar is an adequate matrix to produce a functional food with antihypertensive and prebiotic activity based on spent brewer's yeast bioactive ingredient.

2014Conference object

Open access

Development of a cashew nut coated with bioactive whey peptide extract with antihipertensive

Publication . Pereira, Joana Odila; Amorim, Manuela; Silva, L. B.; Ormenese, R.C.S.C.; Pacheco, M.T.B.; Pintado, Manuela

There is a growing concern in the consumer’s habits seeking healthy foods, which has opened new markets for functional foods. This global demand led to the development of functional foods, searching new ingredients to incorporate into conventional foods. Whey proteins are studied not only from the nutritional and functional properties, but also as a source of peptides that may exert biological functions, particularly antihypertensive activity. These bioactive peptides are released by enzymatic hydrolysis and according the final composition they may exert biological activities. Cashew nut was used as matrix for incorporation functional ingredients due to its nutritional properties conveyed by the high content of folic acid and essential fatty acids. The aim of this study was to develop a cashew nut coated with peptide fraction obtained from whey and to evaluate the antihypertensive activity and consumer acceptance of the new functional cashew nuts. The fraction with MW < 3000 Da was obtained by hydrolysis of whey with Cynara cardunculus followed by nanofiltration to obtain low MW fraction, exhibited very high ACE-inhibitory activity, IC50 12.8 μg /mL protein. The incorporation of peptides (2 %) in cashew nut led to a reduction to values of ACEinhibitory activity, 532.2 μg/mL. However, this is close the values reported by other products in the market claiming antihypertensive activity. In the formulation there is space to increase concentration and biological activity. Nevertheless, it is important to highlight that the antihypertensive activity was not lost even when high temperatures during coating and processing of the product were used. The sensory analysis of the functional cashew nut showed high acceptability by the consumers. Our results suggest that the application of these bioactive peptide extracts with antihypertensive activity in the development of a new snacks with reduce salt content is promising in the improvement of new value-added food products.

2014Conference object

Open access