Isolamento, caracterização e aplicação da fração proteica de grão-de-bico (Cicer arietinum L.) extraída por método alcalino assistido por ultrassom

Abstract

The objective of this research was to test the alkaline method followed by isoelectric precipitation in the extraction of protein from whole chickpea flour, aiming to optimize processing time and improve the technological properties of protein extracts, as well as to characterize and apply these extracts in vegetable burgers. For protein extraction, a BoxBehnken design was used, varying the solid-to-liquid ratio (1:05; 1:10; 1:15), pH (7.0; 9.5; and 12.0), and sonication time (10; 25; and 40 min) at three levels, totaling 15 assays, plus three repetitions at the central point. The most desirable experiment (ED - solid-to-liquid ratio 1:12.5 g mL-1, pH 9.5, and 40 min time) was compared to the extract from the control experiment (EC) and three other experimental conditions evaluated for their technological, chemical, physicochemical, and morphological properties. Subsequently, vegan burgers were formulated with different plant sources for comparison of technological, chemical, and textural properties with a commercial one in a first assay. Then, ED was used in the formulations of vegan burgers at different levels of substitution of whole chickpea flour by chickpea protein extract, generating a second assay, which also compared the use of two natural dyes (açaí and beetroot). The alkaline extraction method assisted by ultrasound did not increase yield but reduced extraction time and improved functional properties, indicating that the extracted protein fraction has potential for use in the development of new food products. In the burger assay, there was an increase of about 24% in yield and moisture retention, and up to 72% in oil retention when comparing burgers from different plant sources to the commercial one, although the latter stood out in protein and fiber composition, providing texture quality. In the assay with the addition of protein extract, there was an increase of up to 2% in yield and about 52% in oil retention. However, natural dyes contributed to increasing fiber content by up to 11%, surpassing that of the commercial one. Further studies with different extraction conditions can be conducted to try to improve the properties of chickpea protein extracts, and enrichment with higher percentages of chickpea protein or combination with other protein extracts can be tested to increase the protein content of vegetable burgers. However, the extracts are viable alternatives for application in food, as the formulations produced in this research indicate a good alternative for those seeking plant-based products.