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Food Engineering

Selective nutrition

USP patents ice cream with added cereals and other products with beneficial additives

JULIANA BOLFARINI HARAMI/USPCereal formulation designed to withstand low temperature of icecreamJULIANA BOLFARINI HARAMI/USP

Live microorganisms combined with a compound called inulin, obtained from plants such as chicory and artichokes, were tested in a chilled dessert with the consistency of an ice cream covered in cereal, among several formulations of functional foods developed at the University of São Paulo (USP), five of which are in the process of being patented. These foods are regarded as functional because, in addition to traditional nutrients, they contain additives that can foster improved health. The ice cream with cereal bar, which was tested and approved by hundreds of people who took part in assessing the product from a sensory standpoint, was a novelty. “There is still nothing similar in the Brazilian market,” says Professor Susana Isay Saad, from the Department of Pharmaceutical and Biochemical Technology at the School of Pharmaceutical Sciences at the University of São Paulo, who coordinated the projects.

The bacteria Lactobacillus acidophilus and Bifidobacterium are added to the ice cream. They have proven probiotic action. “These bacteria improve the balance of the microbiota, intestinal microorganisms, because they compete with pathogenic bacteria, taking over the access the latter would have of coming close to the epithelium [superficial surface] in the intestine,” says Susana. Bacteria of the Lactobacillus and Bifidobacterium genera are often used as probiotic food supplements, as they have been isolated in all parts of the gastrointestinal tract in healthy individuals. Probiotics substantially increase the nutritional and therapeutic value of foods, in that they allow the body to absorb certain vitamins better, in particular those of the B complex, as well as aminoacids, calcium and iron. They also help to strengthen the immune system, by increasing the levels of antibodies and the activity of macrophages, the cells that surround and destroy foreign bodies. “The probiotic microorganisms are added only after the food has been pasteurized , because they cannot survive high temperatures, but before the product is chilled,” explains Susana.

Energy reserve
The composition of the ice cream also includes milk fats and inulin, a substance found in thousands of plants,  that is their energy reserve. In some of them, however, inulin is concentrated in greater amounts, as in the roots of chicory, from which it can be isolated, extracted and concentrated in powder form. “As this is a sophisticated process, few companies in the world have managed to produce this compound,” says the researcher. Inulin is a fructooligosaccharide that is not digested by the stomach, unlike most sugars. It has few calories – some 1.5 kilocalories (kcal) per gram versus 4 kcal/g of sugar and 9 kcal/g of fat – and it can replace sugar in part and help in the treatment of diabetics, because it does not raise the blood sugar level.

Like inulin, oligofructose is also found in vegetables. Both are complex carbohydrates and regarded as prebiotic fibers, because they reach the intestine intact, where they are consumed by beneficial microorganisms, such as the bifidobacteria – a group of microorganisms found in the intestinal flora, which inhibits the development of undesirable bacteria in the digestive tract – the lactobacilli and other probiotic bacteria.

The health benefits from consuming this type of carbohydrate are mainly linked to an increase in the number of bifidobacteria in the colon, which provide protection against infections because they lead to greater acidification, which also contributes to better absorption of minerals, such as calcium and iron. Inulin also plays a functional role similar to that of fibers, which are not digested by our organisms, but  help digestion and the elimination of toxins.

The cereal bar, made from oats, rice flakes, Brazil nuts, honey, soy lecithin and other ingredients, was especially developed to be chilled, because traditional cereal bars go hard when they are submitted to low temperatures. “We tested four different formulations for the cereal bar with  ice cream,” Susana tells us. All the formulations and tests were conducted by master’s degree candidate Juliana Bolfarini Harami, under the guidance of Professor Susana.

The sensory analyses were carried out with a total of 600 people, as each one of the four formulations was tested three times by 50 people. The evaluations were conducted seven days after the product had been made and frozen at -18ºC, then again at 28 days and at 84 days, taking the “best by” date into account. “The product was well liked,” says the research coordinator. Additionally, a comparison of the nutrients and energy value of the cereal-covered ice cream vs. frozen milk-based desserts, such as the ice creams Cornetto, Mega Trufa and two other traditional brands that do not belong to the functional foods category was carried out. “The products, which weighed on average 76 grams, had about 230 calories per portion,” she explains. “Whereas the 70 gram ice-cream with cereal, in the four versions evaluated, had an average of 136 calories a portion

Selected strains
The good results of this research are the fruit of work initiated in 2000. At that time, Susana started researching the use of probiotic cultures in the processing of fresh cheese,  minas frescal kind, with FAPESP aid. In this study, three probiotic bacteria cultures were used for cheese production: Lactobacillus acidophilus, Lactobacillus paracasei and Bifidobacterium animalis. “The strains chosen had been proven to be probiotic,” says Susana. This choice is important, because probiotic effects are specific to given strains. The bacteria added to milk turned out to have excellent potential for improving the performance of the intestine and reducing the dangers of contamination from food . Besides diminishing the acidity of the cheese, Lactobacillus acidophilus reduced the proliferation of contaminating microorganisms in the food itself, which helps to extend the product’s shelf life.

Other studies carried out by the group showed that it is possible to expand the range of products that have a beneficial impact on health. Among the novelties already tested, including sensory analyses, are a quark type cheese, a blancmange, a guava mousse and a margarine, which is being developed by the doctoral candidate Cinthia Batista de Souza, under the guidance of Professor Luiz Antonio Gioielli. All the projects other than the blancmange were financed by FAPESP. The  requests for invention patent were deposited by the USP Innovation Agency.

The production of the quark cheese, developed by Haíssa Roberta Cardarelli during her doctorate, was conducted from a base of quark type cheese, a product with a creamy consistency to which both sweet and savory flavorings can be added. To this base, the probiotics Lactobacillus acidophilus and Bifidobacterium lactis were added. These, when consumed at the same time, can increase the body’s immune response, for instance. The probiotics inulin and oligofructuse were also added. In the several formulations tested, the researchers found that inulin and oligofructose, when combined, improve the sensory characteristics of the cheese. As for the guava mousse, developed by PhD candidate Flávia Alonso Buriti, it appeared that substituting part of the cream in the formulation by inulin results in the Lactobacillus acidophilus becoming more resistant to the simulated conditions of digestion of the product.

The projects
1. Development of probiotic and symbiotic margarine: viability of the probiotic in the product and in vitro (nº 07/59260-0); Type Regular Research Awards; Coordinator Susana Marta Isay Saad – USP; Investment R$ 112,405.19 (FAPESP)
2. Symbiotic aerated dessert: product development and resistance of the probiotic in vitro (nº 05/51317-8); Type Regular Research Awards; Coordinator Susana Marta Isay Saad – USP; Investment R$ 94,125.53 (FAPESP)
3. Development of a symbiotic quark-type cheese (nº 02/14185-8); Type Regular Research Awards; Coordinator Susana Marta Isay Saad – USP; Investment R$ 76,307.16 (FAPESP)