Physicochemical and Sensory Quality of Fermented Milk With Different Blends of Theobroma grandiflorum and Theobroma cacao

The production of fermented milk added of fruits is a considerable alternative for dairy industries and can constitute a rational and logical form of different types of processing, in various flavors, being part of a promising market in the Brazilian scenario. In view of the above, the present study aimed to research the biotechnological processes of production of fermented milk with different blends of cupuaçu (Theobroma grandiflorum) and cocoa (Theobroma cacao). The experimental design used was completely randomized, with six treatments, consisting of different concentrations of pulp (blends) of cocoa and cupuaçu (T1: 100% cupuaçu, T2: 100% cocoa, T3: 50% cupuaçu + 50% cocoa, T4: 60% cupuaçu + 40% cocoa, T5: 70% cupuaçu + 30% cocoa, and T6: 80% cupuaçu + 20% cocoa) and four replicates. The results showed that the production of fermented milk added with 100% cocoa and 70% cupuaçu + 30% cocoa showed good lightness, yellowish color, slight sweetness and moderate acidity, according to the data of a*, b*, %Brix and pH. Fermented milk added of 100% cupuaçu, 70% cupuaçu + 30% cocoa and 60% cupuaçu + 40% cocoa had greater acceptability in regard to color and texture, while fermented milk added of 70% cupuaçu + 30% cocoa had the highest values of acceptability for aroma and flavor. The production of fermented milk with the use of different regional raw materials is feasible, because there is great potential as a sustainable alternative, and the addition of pulp of Amazonian fruits promotes greater nutritional and sensory value in fermented milk, contributing to the regional economy.


Introduction
The Brazilian Amazon is rich in the diversity of plants that are still little explored by most of the population and that can become a food alternative of high nutritional value. Among the fruits of great importance for the Amazon region, cupuaçu (Theobroma grandiflorum) and cacao (Theobroma cacao) stand out as the most commercially exploited and are among the tropical fruits of excellent commercial value at the national and international levels. In the case of cupuaçu, the pulp is the most consumed part of the fruit and, due to the characteristics of acidity, pectin content, active aroma, pleasant flavor, richness in volatile compounds and mineral salts, it is an important raw material for the processing industry (Vriesman et al., 2009;Martins, 2008). Cocoa fruit contains substances with various functional properties, such as quercetin, rutin, ferulic, caffeic and coumaric acids (among others), catechins, methylxanthines (theophylline, theobromine, caffeine, etc.), various polyphenolic acids and flavonoids (Ferrari & Torres, 2002), which are useful in the treatment of various pathologies.
The similarity between cupuaçu and cocoa seeds has aroused scientific interest, because chocolate-like products and chocolate drinks of excellent quality in terms of flavor can be obtained from fermented and toasted cupuaçu seeds. In this perspective, the use of pulp of Amazonian fruits or fermented seeds in formulations of fermented milk can give pleasant taste, improve nutritional value, and promote scientific and technological development. Milk has been constantly studied due to its nutritional profile, potential health benefits attributed to its consumption and the use of probiotic bacteria. In the latter case, the bacteria belonging to the genus Lactobacillus, such as the Lactobacillus casei, Lactobacillus casei shirota, Lactobacillus paracasei, Lactobacillus acidophilus and Lactobacillus zeae, are very often employed as probiotic supplements for food, especially for fermented milk (Alonso & Isay, 2007).
Fermented milks, according to the Technical Regulation of Identity and Quality of Fermented Milk (Brazil, 2007), are products added or not of other food substances obtained by coagulation and reduction in milk pH, or reconstituted, added or not of other dairy products, by lactic fermentation through the action of cultures of specific microorganisms, and these must be viable, active and abundant in the final product during its shelf life (Brazil, 2007).
Thus, the production of fermented milk added of fruits is a considerable alternative for dairy industries and can constitute a rational and logical form of different types of processing, in various flavors, being part of a promising market in the Brazilian scenario. In addition, the potential of the Amazon region regarding the investment in food technology creates the opportunity for the discovery of new horizons for products with different treatments that meet the national and international consumer public, through the creation and exploitation of Amazonian products and species.
In view of the above, the present work aimed to research the biotechnological processes of production of fermented milk with different blends of cupuaçu (Theobroma grandiflorum) and cocoa (Theobroma cacao).

Material and Methods
The experiment was conducted at the premises of the Food Agroindustry of the Federal Institute of Education, Science and Technology of Rondonia, Colorado do Oeste Campus, in the municipality of Colorado do Oeste, RO, Brazil, at the geographic coordinates 13°06′ S and 60°29′ W, with an average altitude of 407 meters.
The milk used to conduct the test was produced in the Animal Science sector of the Federal Institute of Education, Science and Technology of Rondonia, Colorado do Oeste Campus, and supplied to the Food Agroindustry. Initially, the milk was skimmed to have a maximum fat content of 0.5 g/100 g, according to the Normative Instruction nº 62 of 2011, in slow pasteurization, raising the temperature to 65 ºC for thirty minutes, followed by cooling to the incubation temperature of the fermenting microorganisms at 37 ºC (Lactobacillus casei shirota), in a rigorously controlled environment for a period of 7 hours. Milk fermentation occurred until the pH of the medium reached values of 4.0 (±0.25). This pH interval was determined considering the sensory and conservation characteristics of the product.
The production of fermented milk in the presence of the different blends of cocoa and cupuaçu was performed by adding concentrations of cocoa pulp and concentrations of cupuaçu pulp, considering the aforementioned treatments. After milk pasteurization, syrup was prepared and added, part of it constituted by 10% sugar, in each sample, respecting the equivalent concentrations of pulp for each treatment (blends of cupuaçu and cocoa).
Treatments that, after processing, showed apparent viscosity visually similar to/compatible with that of fermented milk existing on the market were subjected to physicochemical analyses: pH, acidity, colorimetric parameters L* (lightness ranging from 0 [totally black] to 100 [totally white], a * (-80 green to +100 red) and b * (intensity from -50 blue to +70 yellow), and °Brix.
The sensory acceptance test (attributes: color, texture, consistency, aroma, flavor and overall aspect) was conducted at seven days of storage. Sensory evaluation of acceptance was performed by untrained tasters (40 tasters) and considering the scores according to the hedonic scale with values from 1 to 9 points (1-disliked extremely, 2-disliked very much, 3-disliked moderately, 4-disliked slightly, 5-Neither liked nor disliked, 6-liked slightly, 7-liked moderately, 8-liked very much and 9-liked extremely), indicating how much they liked or disliked the color, texture, aroma, flavor and overall aspect of products.
Physicochemical and sensory results were subjected to analysis of variance and the differences between means were compared by Tukey test at 5% significance level, using Sisvar software.

Results and Discussion
The results showed significant effects (p ≤ 0.05) of the treatments composed of different concentrations of cacao and cupuaçu pulp on the parameters L*, a*, b*, °Brix, pH and sensory analysis (Tables 1 and 2). igher in the tr nference that th b* (Figure 1).

Conclusions
Fermented milk added of concentrations of 100% cacao and 70% cupuaçu + 30% cacao showed good lightness, yellowish color, slight sweetness and moderate acidity, according to the data of a*, b*, %Brix and pH.