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PEDRO HENRIQUE FREITAS CARDINES

Título da Dissertação:  DETERMINAÇÃO DAS PROPRIEDADES FUNCIONAIS DA SEMENTE DE MORINGA OLEIFERA E SUA APLICAÇÃO NA FORMULAÇÃO DE IOGURTE.

Orientadora: Profa. Dra. Angélica Marquetotti Salcedo Vieira

Data da Defesa: 28/02/2014

 

RESUMO GERAL

 

Introduction

The Moringa oleifera belongs to Moringaceae family has seeds with high protein content, are widely studied due to its fining power related to its clotting power waters. However studies that relate their properties applied to food systems are still scarce.

 Aims

The present study aimed to characterize the physico-chemically moringa seeds, as well as their functional properties and apply the moringa seeds in a food system to obtain information about the technological and functional profile of the same.

 MATERIALS and Methods

The seeds of moringa used in the trials were from Aracaju - SE. Seeds were approved upon, cleaned and peeled for further grinding and drying (40ºC). For the first part of the work the physicochemical characterization of moringa seed flour was taken, analysis of protein, fat, ash, moisture and carbohydrate were performed. Characterization of the functional properties was established by performing tests of water absorption and oil emulsifying a function of pH, foaming ability as a function of pH, temperature effect on protein solubility of moringa seed flour according to Lowry. Zeta potential was measured using a zeta potentiometer brand Beckman Coulter, model DelsaNano C and evaluation of antioxidant activity (ABTS and DPPH) of the protein extract of moringa seed was performed using TROLOX as standard. In the second part of this work was a yogurt containing aqueous extract of moringa seed in different concentrations (0, 5, 10 and 15 ml of extract/liter of yogurt). To obtain yoghurt milk pasteurization (15 min at 85ºC) was then carried the temperature was reduced to 43ºC and made inoculum of lactic yeast and different proportions of aqueous extract of moringa. The fermentation was performed in an oven at 43ºC with pH monitoring until it reached pH 4.6. After the fermentation , was made an initial cooling to approximately 20ºC, and the breakdown of the clot was done by manual shaking for 30 seconds. Then, the final cooling was done in a bath of water and ice and yoghurts were stored in the refrigerator at 5ºC until time of analysis. Microbiological characterization was performed by counting the lactic bacteria (Streptococcus thermophilus, acidophilus and Bifidobacterium) of yogurts from decimal dilutions. Physical and chemical analyzes (total solids, pH, total acidity, ash, protein and fat) yogurt containing aqueous extract of moringa seed, all methods were performed by AOAC. The susceptibility to syneresis centrifuging samples of 25 grams of yogurt (Refrigerated centrifuge MPW - 351R, MPW INTRUMENTS MED) was measured at 2500 G for 10 minutes at a temperature of 5ºC. The difference between the total mass of the precipitate and corresponds to syneresis, which was expressed in percentage (% m/m). Rheological analyzes were performed on rotational Thermo Haake, equipped with plate/plate geometry with 60 mm diameter. A band gap of 1 mm and a sample volume of 2 ml were used. This machine has temperature control Haake Mars Controller Peltier-type, whose value was set to 10 and 25ºC. The flow curves and viscosity were obtained by determining the stress and viscosity versus shear rate, respectively. The rate ranged from 0.02 to 700 s-1 (upslope) and between 700 and 0.02 s-1 (downslope). Being the total time of analysis 60 seconds, collecting 100 points in this range. For sensory analysis revealed four formulations were prepared yogurt being one control without addition of moringa extract, and three containing 5, 10 and 15 mL of the extract of Moringa per liter of yogurt. Preferably a test day was conducted after the production of yogurt, evaluated / judged by 100 untrained assessors who evaluated color, aroma, flavor, texture and overall appearance of the product. All assays were performed in triplicate and analyzed by Statistc 8.0 software applying ANOVA, using the Tukey test with 5 % significance.

 Results and Discussion

Crude Protein (37.47), lipids (36.89), ash (3.52): For the first part of this work the results of physicochemical characterization were similar to those found in the literature, the following values (%) were found, humidity (4.02) and carbohydrates (16.17). The contents of the functional properties of water absorption and oil were 1.18 ml of oil/g sample and 1.13 mL of water/g sample, respectively. These results show that moringa seed meal can be used as improving texture due to water absorption and fixation of aroma due to their oil absorption. The emulsifying activity of moringa seed was higher at neutral pH (7.0) and alkaline (8.0 and 9.0). This may indicate that this pH range has a higher rate of unfolding of the proteins than at low pH. The foaming ability of at pHs between 6.5 to 8.0 varied from 83.6 to 90.4%, resulting in a good foaming ability and can be added to products such as pastries, meringues, blankets candy, etc. But for pHs 3.0, 5.0 and 9.0, this capacity drops to below 80%, making the use of this property in food systems. The protein solubility begins to be compromised significantly from the temperature of 80˚C, causing loss of solubility and some functional properties in food proteins. Evaluating the effectiveness of the antioxidant moringa seed water extract by the methods sequestration of free radicals ABTS was obtained return value from the average trolox equivalent antioxidant activity equal to 1.39 (100 g mmol-1) and 2.33 (mmol 100 g-1) by the DPPH method. The results of the second part of this study include the physical-chemical characterization results showed that within the compliances stipulated by the current legislation being: fermentation time ranging from (210-215 min.), Titratable acidity (0.77 to 0.81% ác. lactic acid), total solids (14.74 to 15.22%), fat (2.83 to 3.50%), protein (0.47-0.62%), ash (from 0.72 to 0.82%), pH (4.58 to 4.68). In the analysis of susceptibility to syneresis has been that the higher the concentration of extract of moringa, the lower the loss syneresis. The loss of product was less syneresis compared to the control sample, reaching a difference of 7.44% in the third week, comparing treatment with control sample was added 15 mL of extract/L of yogurt. The yogurt is made by rheology typical of a thixotropic fluid (shear thinning) behavior, having a structure which is broken function of time and shear rate, confirming the behavior of the pseudoplastic fluid as yogurt. And the sample containing the highest concentration of moringa extract showed the highest viscosity and cohesiveness during the four weeks. The results obtained in the sensory analysis we note that in fact the tasters differed in texture and attributed the highest score for the sample that had the highest amount of moringa extract, no significant difference for the other issues in question.

 

Conclusion

The physicochemical characterization of moringa seeds shows great potential for exploitation when it comes to proteins and lipids, when compared to other plant sources. Taking into account the analysis of the functional properties of moringa seed flour, it can be concluded that it has good characteristics for analyzes and may be used in formulating a range of food products. The application of moringa seed extract in yoghurt showed better results for the sample containing the highest amount of this extract. The use of moringa seed extract resulted in interesting features, since its addition increased the protein content collaborating with increasing viscosity and resulting in lower syneresis due to the strengthening of the protein network, resulting in a firmer yogurt texture, having a better acceptance by the judges.

 Key Words: Moringa oleifera Lam, protein, yogurt, Functional.

 

Artigos Publicados Vinculados a Dissertação:

https://doi.org/10.1016/j.cej.2015.04.045