Mónica Rubilar

The main objective of this study was to develop an optimized formulation of soup powder enriched with omega‐3 fatty acids. For this purpose, the process conditions for optimizing the microencapsulation efficiency (ME) of linseed oil by spray drying were determined using the Taguchi methodology with an orthogonal array L₄(2³). The effect of the variables on the ME, such as wall material concentration (25 and 30%), linseed oil concentration (14 and 20%), and wall material type (gum arabic GA; and a mixture maltodextrin/GA), was evaluated. The oxidative stability of the microcapsules obtained were determined by the Rancimat method, and a morphological and size characterization of microcapsules was performed by scanning electronic microscopy, confocal microscopy, and laser diffraction. The optimization of the soup formulation was reached by means of RSM, using the central composite design, two control factors (salty taste and consistency), and 11 design points. The hedonic test was applied to measure the acceptability of the optimized formulation. Chemical characterization of optimized soup and its oxidative stability were also evaluated. This study resulted in a healthy soup enriched with omega‐3 which was highly acceptable to consumers.Practical applications: Linseed oil is a healthy and nutritive oil, very rich in unsaturated fatty acids such as omega‐3. In addition to protecting the oil against oxidative damage, the microencapsulation of oils in a polymeric matrix (mainly polysaccharides and proteins) also offers the possibility of controlled release of the lipophilic functional ingredient and can be useful for the supplementation of foods with PUFA. The soup powder enriched with microencapsulated linseed oil as a source of omega‐3 formulated in this study will contribute to the development of foods according to the functionality requirements of current consumers and markets.

An alternative to solve the problem of the overall deficit of proteins has been the use ofdefatted cakes generated by the extraction of oil from vegetable sources such as rapeseed, soybean, lupin, etc. This process at the same time increases the protein content, making this feasible to be used to enrich some types of food. This is the case of the chilean hazelnut (Gevuina avellana, Mol), monotypic species characterized by their high percentage of oil (50%) and whose defatted cake isolated protein could be used to obtain an isolated protein. For this purpose optimized conditions of extraction of protein were carried out using the surface response methodology (SRM) and a central composite design with three independent variables: time of contact of the cake with the solvent, sample/solvent ratio and pH was used. All variables were controlled at five different levels. The data were subjected to an analysis of regression and ANOVA, the first to determine the polynomial equation and the second to select the control factors with significant effect on the extraction of the protein. The best combination of factors turned out to be: time between 30 and 40 minutes, pH between 9 and 9.5 and a relationship sample/solvent between 1/15 to 1/16 with a final yield of 76%. The physical characteristics were: density 0,504 g/cm3, compaction 43, 34% apparent and pale yellow. Proximal analysis showed a concentration of protein of 76%, 13%, raw fiber carbohydrate 0.68% and oil 1.29%. With regard to the functional properties emphasized water absorption (320 g/100 g), absorption of oil (410 g/100 g) and foaming capacity (221%).

The main objective of this study was to evaluate the effect of incorporating polyphenolic‐enriched fractions from murta leaves on the oxidative stability of linseed oil microencapsulated by spray drying. For this purpose, polyphenol‐enriched fractions from murta leaves were separated by gel permeation chromatography and chemically characterized. The oxidative stability of microencapsulated linseed oil (MLO) with antioxidants was evaluated in storage conditions at 25°C for 40 days. The antioxidant effects of the polyphenolic fractions and commercial antioxidants (BHT and trolox) on microencapsulated oil were evaluated by the value of conjugated dienes, peroxide, and p‐anisidine. In the initiation step of the oxidation, no significant oxidation delay (p>0.05) in MLO containing fractions F₆, F₈, or BHT and trolox was observed. However, in the termination step of the oxidation, the addition of fractions F₆, F₈, and BHT and trolox decreases significantly (p ≤ 0.05) the rancidity in MLO. Furthermore, the results of this study demonstrated the importance of the addition of natural antioxidants such as fractions of murta leaf extract in microencapsulated linseed oil to increase its resistance to oxidation.Practical applications: For incorporating linseed oil, a source of omega‐3 fatty acids, in the diet it is necessary to protect it against oxidative rancidity, the main cause of deterioration that affects food with a high unsaturated fat content. Microencapsulation is effective in retarding or suppressing the oxidation of unsaturated fatty acids and natural plants extracts are effective in inhibiting the lipid oxidation of microencapsulated oil. The use of process technology and a natural additive is expected to increase storage stability and enable its use in dry foods such as instant products. Linseed oil can be used in human nutrition as well as in animal feed as a replacement for fish oil.

In view of the interest in the role of foodstuffs in improving wellbeing and health, the object of this study is to distinguish consumer typologies in Temuco, La Araucanía Region, Chile, according to their preferences for different functional ingredients, flavouring, colouring and price in yoghurt. A semi-structured survey was applied to 400 supermarket customers. The respondents ordered eight alternative yoghurts according to their preferences, with different functional ingredients (fibre, antioxidants), flavourings (sugar, sweetener), colouring (natural, artificial) and three price options, for a conjoint analysis with fractional factorial design. Variables affecting knowledge of "functional food" were evaluated using a binomial logit model. It was determined by conjoint analysis that in general a preference existed for yoghurt containing fibre, sweetener, natural colouring, and at the lowest price. Three typologies were distinguished by analysis of hierarchical conglomerates: the majority segment (48.8%) displayed a greater preference for fibre; the second (41.7%) also preferred fibre, but gave first priority to artificial colouring and preferred a higher price. The minority (9.5%) was the only segment to prefer antioxidants. The typologies differed significantly in satisfaction with their food-related life, knowledge of the function of fibre and presence of cancer and obesity in some member of the respondent's family. The binomial logit model was significant (P < 0.01), indicating that if the consumer has a job or has had access to information on functional foods, the probability increased of knowledge of what these mean. There was thus majority acceptance of yoghurt enriched with fibre and with added sweetener.

Response surface methodology (RSM) was employed to evaluate the effect of flow (2, 2.5 and 3 mL/min) and gradient of elution (A: water; B: methanol, step 35–45–55% B, 40–50–60% B and 45–55–65% B) on polyphenols separation from organic-aqueous murta leaves extract by Sephadex LH-20 chromatography. Six fractions were collected from extracts to which response was measured as total polyphenols and antimicrobial activity against Staphylococcus aureus. The models obtained showed that variables are significant for the inhibition activity of fraction 6 against S. aureus (p ≤ 0.05). The best separation condition of this fraction was obtained in the area where the flow is 2.5 mL/min (medium level) and the mobile phase contains a lower methanol percentage. The inhibitory activity of fraction 6 was explained by the flavan-3-ol compounds of lower molecular weight, not present in other fractions.