Michely Capobiango

Enzyme-catalyzed Production of Oligopeptides from Skim Milk

With the aim of preparing high nutritional dietary supplements containing oligopeptides from skim milk, an Aspergillus protease, papain and pepsin, separately or in association, were used in different enzyme:substract ratios (1%, 2% and 4%). The fractionation of peptides according to their size was used to evaluate the nutritional quality of protein hydrolysates. The hydrolysates were fractionated by high-performance liquid chromatography in size-exclusion mode and the rapid method of Correct Fraction Area was used for the quantification. In general, the isolated action of the enzymes produced better peptide profiles than their simultaneous use, especially in terms of a higher amount of oligopeptides, which reached 56%.

Optimization of enzyme assisted processes for extracting and hydrolysing corn proteins aiming phenylalanine removal.

Two enzyme assisted processes were studied in this work, protein extraction and hydrolysis, aiming phenylalanine (Phe) removal from corn. For protein extraction, a protease of Bacillus liccheniformis was used and the effect of temperature (55 and 60°C) and time (1, 5, 15 and 24 h) was evaluated. For Phe removal, a pancreatin was used for hydrolyzing corn proteins and the activated carbon (AC) was the adsorbent support. In this case, the influence of several parameters was estimated, such as protein extract concentration, E:S ratio, use of freezedrying, protein: AC ratio and way of using AC. The efficiency of Phe removal was evaluated by second derivative spectrophotometry, measuring the Phe content in the corn flour as well as in the hydrolysates after AC treatment. The results showed that the time and the temperature influenced the protein extraction yield and the best results were obtained at 55°C, after 5 h, 15 h and 24 h of reaction, having reached an average extraction yield of 85.3%. The removal of Phe, changed from 68.63 to 97.55%, and its final concentration from 18.80 to 240.75 mg/100 g hydrolysate. The condition that produced the highest Phe removal was the one using a protein extract concentration = 1%, E:S = 1 or 2%, pH 9, temperature = 25°C, protein: C = 1:88.5, using three types of AC and freezedrying (hydrolysates H1 and H2). However, this condition presents some disadvantages such as the use of freezedrying, which highly raises the process cost, and a non-controlled and non-repeatable reaction. Among the samples with no freezedrying stage and more controllable reaction (H9 and H10), H10 is the best one, since it showed smaller Phe content (149.27 mg/100 g) using three types of AC, which is advantageous from the technical point of view. The reduction of the protein: AC ratio, for these two hydrolysates (H9 and H10) was not beneficial for Phe removal, leading to higher Phe content.

Evaluation of Methods Used for the Analysis of Volatile Organic Compounds of Sugarcane (Cachaça) and Fruit Spirits

Sugarcane spirits are defined as beverages with an alcohol content ranging from 38 to 54xa0% v/v at 20xa0°C, obtained from the simple alcoholic distillation of sugarcane or fermented sugarcane must. Fruit spirits may be obtained directly from fruit or from fruit must that may or may not contain seeds by distillation, and present specific organoleptic characteristics and an alcohol content of 36 to 54xa0% v/v at 20xa0°C. The physicochemical and sensory qualities of these beverages are dependent on the nature and quality of the raw materials, fermentation, distillation and aging, and are organoleptically characterised by the presence of volatile organic compounds (VOC) (organic acids, aldehydes, esters, higher alcohols, terpenes, lactones and others). This paper presents studies performed to evaluate VOC in spirits. Among the volumetric and instrumental methods described to evaluate VOC in spirits, chromatographic methods are the most cited. Chromatographic techniques employed include high performance liquid chromatography, gas chromatography with flame ionisation detection, gas chromatography with mass spectrometric detection and two-dimensional gas chromatography with time-of-flight mass spectrometry.

Study of Some Functional Properties of Casein: Effect of pH and Tryptic Hydrolysis

The trypsin was used to hydrolyze commercial casein at varied times and pH range. The functional properties studied were the emulsifying capacity (EC), the emulsifying activity index (EAI), and the emulsion stability (ES). The dispersed phase used was corn oil. The tryptic hydrolysis was beneficial to the solubility and EC of casein in practically all pH values and reaction times. In case of EAI, this same effect was less intense and was observed only in acid region (pH 3.0 to 5.0), while for ES the trypsin action was mainly deleterious in almost all pH range and reaction times.

Action of Pepsin on Emulsifying Properties of Globin

The emulsifying properties of bovine globin, extracted by the acidified acetone method, were studied at different pH values and after several times of peptic-hydrolysis. The emulsifying capacity, the emulsifying activity index, and the emulsion stability were determined. In general, the peptic hydrolysis was disadvantageous for the emulsifying properties of globin, since it only increased the emulsifying capacity (at pH = 3.0, after 30 and 60 minutes hydrolysis; at pH = 4.0, after 10 to 60 minutes hydrolysis), and the emulsifying activity index (at pH = 5.0 after 60 minutes hydrolysis; at pH = 6.0 after 15, 30, and 60 minutes hydrolysis). This treatment reduced the emulsion stability in almost all conditions studied.

Hidrolisados protéicos de arroz com baixo teor de finilalanina, obtidos pela ação da corolase PP e uso do carvão ativado

A partir do extrato proteico obtido em meio alcalino, empregou-se a corolase PP no preparo de seis hidrolisados enzimaticos de arroz, visando o desenvolvimento de formulacoes dieteticas para fenilcetonuricos. O procedimento de passagem por coluna contendo carvao ativado foi utilizado na remocao de fenilalanina (Phe) dos hidrolisados. O teor de Phe nos extratos proteicos de arroz e seus hidrolisados, apos tratamento com carvao, foi determinado por espectrofotometria derivada segunda. O teor final de fenilalanina nos hidrolisados variou de 0,39 a 68,34 mg 100 g-1, o que corresponde a uma remocao de 84 a 100%. A distribuicao dos peptideos nas amostras, de acordo com o tamanho da cadeia, foi estudada como um dos criterios para a avaliacao da qualidade nutricional dos hidrolisados. O fracionamento dos peptideos foi realizado por CLAE de exclusao molecular e, para a quantificacao empregou-se o metodo rapido da area corrigida da fracao. Os resultados indicaram que o maior teor de oligopeptideos foi obtido quando se empregou a corolase PP em uma relacao E:S de 1%, e uma concentracao proteica inicial de 1,56 g 100 mL-1.

Extração química e enzimática das proteínas do fubá de milho

Diferentes metodos quimicos e um enzimatico foram testados para extracao das proteinas do fuba de milho. A avaliacao do rendimento da extracao proteica foi feita pela determinacao do teor de proteina e de solidos totais dos residuos obtidos. Para a extracao quimica das proteinas, uma solucao alcalina, isoladamente ou em associacao com etanol, foi empregada como solvente. O metodo alcalino-alcoolico sequencial foi o mais eficiente, dentre os metodos quimicos testados, tendo alcancado 88,2% de rendimento. Por outro lado, o metodo alcalino (75,5% de rendimento) apresenta a vantagem de nao empregar etanol, reduzindo os custos do processo, pois se evita a etapa de remocao desse solvente. Para a extracao enzimatica, foi utilizada uma protease de Bacillus liccheniformis. As variaveis, tempo e temperatura, empregadas no metodo enzimatico influenciaram no rendimento da extracao proteica do fuba de milho. Os melhores resultados foram obtidos em 5, 15 e 24 h a 55 °C, que nao apresentaram diferenca significativa, sendo que a condicao mais vantajosa do ponto de vista economico foi a de 5 h a 55 °C com um rendimento de 83,8%.

Extração enzimática das proteínas da farinha de arroz

The enzymatic extraction of proteins from a commercial rice flour was studied in this work. In order to increase the Protein Extraction Yield (PEY), the following parameters were evaluated: enzyme type (alkaline and neutral protease); temperature (40, 50 and 60 °C); pH (9.5, 10.5 and 11.0); physical treatment of the sample (no treatment; Ultra-Turrax at 16.000 rpm and ultrasound at 120 W, both for 5, 10 and 15 minutes); enzyme:substrate ratio (E:S) of 5:100 and 10:100 and initial concentration of raw material (1:3, 1:5 and 1:10 w/v). The PEY was calculated using the protein contents of rice flour and the extraction residues. The results showed that the best condition for protein extraction, which gave the highest PEY (63.4%), was that using an initial concentration of raw material of 1:10 (w/v), no physical treatment, pH 10.5, the alkaline protease, an E:S of 10:100, at 50 °C.

Assessment of volatile organic compounds from banana Terra subjected to different alcoholic fermentation processes

Banana characteristics could provide yeast growth and support the action of yeast to produce beverages. The effects of enzymatic treatment, centrifugation, commercial yeast and two selected strains of Saccharomyces cerevisiae were investigated using the fermented banana Terra. Volatile organic compounds (VOCs) were determined by solid phase microextraction using gas chromatography mass spectrometry. The results showed that the condition employing enzymatic treatment, centrifugation and wet commercial yeast provided maximum ethanol yield (86%) and effiency (98%). Twenty-two compounds of distinct chemical classes were analysed including alcohols, esters, acids and aldehydes. The concentrations of the VOCs differed depending on the fermentation condition and were more influenced by using different yeasts. The limits of detection and quantification ranged from 0.056 to 2.694 mg L–1 and 0.057 to 2.904 mg L–1 respectively. Among the most prevalent VOCs the higher alcohols ranged from 353 to 1017 mg per 100 mL of anhydrous alcohol. The fermented banana studied showed a composition similar to other fermented fruit pulps.