Optimized formulation of a Physalis peruviana L. fruit nectar: physicochemical characterization, sensorial traits and antioxidant properties.

The aim of this research was to develop and characterize an innovative nectar formulation of Physalis peruviana fruits from the Argentinean Northern Andean region with optimized proportions of pulp and sucrose that maximizes the antioxidant activity and with good sensorial acceptance, using the response surface methodology as optimization strategy. Physicochemical characteristics (total soluble solids, titratable acidity and pH), antioxidant activity (measured as the free radical scavenging activity against DPPH·) and sensorial attributes (color, acidity, sweetness, texture, aroma and overall acceptance) were evaluated in a series of nectar formulations. A significant correlation between overall acceptance and antioxidant activity contributed to achieve the objective outlined. The mathematical modelling defined a nectar with 65% fruit juice and pulp and 8% sucrose; this nectar presented absence of indicator microorganisms (aerobic mesophilic microorganisms, molds and yeasts, Salmonella spp., total coliforms, and Staphylococcus aureus coagulase positive) despite having no added preservatives. ß-carotene and vitamin C contents (1.13 ± 0.02 and 16.56 ± 0.52 mg/100 mL respectively) and antioxidant activity towards DPPH· (EC50: 2.43 ± 0.07 mg/mL), ABTS·+ (3.48 ± 0.07 µmol Trolox/mL) and FRAP (10.16 ± 0.10 µmol Trolox/mL), make this nectar a functional food with potential for the food industry.

Enhanced oxidative stability of meat by including tannin-rich leaves of woody plants in goat diet.

Objective: The aim of this study was to evaluate the effect of dietary incorporation of tannin-rich woody species on meat oxidative stability, carcass traits and meat quality in goats. Methods: Two tannin-rich species were tested using a three-treatments feeding trial, where treatments consisted of: Larrea divaricata and Acacia aroma both at 12.5% in dry matter basis of the diet and a control diet (alfalfa hay). All feeding diets were iso-protein and iso-energy. Carcass conformation, carcass compactness, carcass fatness and subcutaneous fat deposition were evaluated. Intake, liveweigh, Longissimus thoracis et lumborum muscles of goats were analyzed in order to evaluate quality parameters such as pH value, instrumental color evaluation, water holding capacity, total phenolic content, antioxidant activity, meat oxidative stability and fatty acid profiles in meat. Results: Feed intake, liveweight gain, carcass and meat traits did not differ among treatments. Changes in meat lipid profile among treatments were observed for oleic and elaidic acid contents. Meat total phenolic content and antioxidant activity did not differ among treatments; although, meat oxidative status after storage at room temperature, as well as under refrigerated and frozen conditions were different between control and both supplemented groups. Conclusion: The inclusion of Acacia aroma and Larrea divaricata leaves in goat diet enhanced meat oxidative stability. Modulation of the ruminal biohydrogenation of fatty acids produced by condensed tannins of these plant species need to be further investigated.

Encapsulation of cactus (Opuntia megacantha) betaxanthins by ionic gelation and spray drying: A comparative study.

The encapsulation of betaxanthins from orange Opuntia megacantha fruits was performed as a stabilisation strategy for these natural pigments. Betaxanthin-rich extract (BE) was encapsulated by two methodologies, spray drying (SD) and ionic gelation (IG). Encapsulates were obtained by using two encapsulating agents (EA), a mixture of maltodextrin-cactus cladode mucilage and sodium alginate (SA) for SD and IG, respectively. Their properties were compared with the freeze-dried cactus fruit pulp (CP) as control. Total betaxanthin content, moisture content, water activity (aw), particle size, morphology by SEM, colour parameters (CIELab), and thermogravimetric properties were analysed in the encapsulates. Additionally, the antioxidant activity, total dietary fibre content, and pigment stability of encapsulates under two relative humidity conditions were also evaluated. The results showed that the encapsulation technique, EA concentration, and the BE/EA ratio affected the particle size and morphology, the glass transition temperature, and the mass loss of encapsulated materials. The best pigment stabilisation was obtained for the SD capsules, although both encapsulation techniques allowed improving the pigment stability in comparison with the CP taken as control. These results provided evidence that betaxanthins from Opuntia megacantha have the potential to be used as natural pigments, soluble in water, with functional properties for the food industry.

Lactic Acid Fermentation Improved Textural Behaviour, Phenolic Compounds and Antioxidant Activity of Chia (Salvia hispanica L.) Dough.

In this work, autochthonous lactic acid bacteria (LAB) were isolated from chia (Salvia hispanica L.) dough and selected on the basis of the kinetics of acidification and proteolytic activity. Strain no. C8, identified as Lactobacillus plantarum C8, was selected and used as starter to obtain chia sourdough. Lactic acid fermentation increased the organic acid mass fractions (lactic, acetic and phenyl lactic acids to 12.3 g, 1.0 g and 23.8 µg per kg of dough respectively), and antioxidant activities, which increased by approx. 33-40% compared to unfermented chia flour dough. In addition, total phenolic content increased 25% and its composition was strongly modified after 24 h of fermentation by L. plantarum C8. Chlorogenic acid was only found in the fermented dough (2.5 mg/g), while ferulic acid was detected from the beginning of fermentation, being 32% higher in chia sourdough (5.6 mg/g). The use of fermented chia sourdough improved the overall characteristics of white bread, including physical (e.g. reduced hardness and chewiness of the crumb) and antioxidant properties (25% on average), compared to the white bread. These results indicate that the use of chia sourdough could be a promising alternative to improve the technological and antioxidant properties of wheat bread. In addition, this work has shown, for the first time, that lactic acid bacterium is able to ferment chia dough, improving its overall characteristics.

Encapsulating betalains from Opuntia ficus-indica fruits by ionic gelation: Pigment chemical stability during storage of beads.

Betalain encapsulation was performed by ionic gelation as a stabilization strategy for these natural pigments. Betalains were extracted from purple cactus fruits and encapsulated in calcium-alginate and in combination of calcium alginate and bovine serum albumin. Beads were characterised by scanning electron microscopy and thermal analysis using differential scanning calorimetry and thermogravimetry. Moisture sorption isotherms were determined. Bead morphology was affected by matrix composition. Pigments storage stability was evaluated at different equilibrium relative humidity and temperatures. Pigment composition of beads was determined by HPLC-MS-MS and degradation products were also analysed after storage; betalamic acid being the major one. Both types of matrices protected the encapsulated pigments, being their storage stability better at low relative humidity than that of the non-encapsulated control material. Antiradical activities of beads were proportional to remaining betalain contents. At high relative humidity, there was no protection and low storage stability was observed in the samples.

Microencapsulation of betalains obtained from cactus fruit (Opuntia ficus-indica) by spray drying using cactus cladode mucilage and maltodextrin as encapsulating agents.

The microencapsulation of betalains from cactus fruit by spray drying was evaluated as a stabilization strategy for these pigments. The betalains used as active agent were extracted from purple fruits of Opuntia ficus-indica (BE) and encapsulated with maltodextrin and cladode mucilage MD-CM and only with MD. The microcapsulates were characterized by scanning electron microscopy (SEM), thermal analysis (TGA-DSC), tristimulus colorimetry, as well as, their humidity, water activity and dietary fiber content were also determined. The active agent content was measured by UV-Vis spectrophotometry and its composition confirmed by HPLC-ESIMS. A pigment storage stability test was performed at 18 °C and different relative humidities. The addition of CM in the formulation increased the encapsulation efficiency, diminished the moisture content, and allowed to obtain more uniform size and spherical particles, with high dietary fiber content. These microencapsulates are promising functional additive to be used as natural colorant in the food industry.

Immobilization of caffeic acid on a polypropylene film: synthesis and antioxidant properties.

The immobilization of caffeic acid (CA) on a polypropylene (PP) film was successfully performed through the covalent binding of the caffeoyl chloride on a modified polymeric surface of PP films grafted with hydroxyethyl methacrylate as monomer (PP-g-HEMA). The different reaction steps were monitored by FT-IR spectroscopy. The synthesized films were characterized by Folin-Ciocalteu method by measuring the available phenolic groups as caffeic acid equivalents linked to the surface. The antioxidant efficiency of the modified polymers was evaluated by typical spectrophometric methods, such as the bleaching of radicals DPPH(•) and ABTS(•+), and the inhibition of the enzymatically induced coupled oxidation of linoleic acid and betacarotene. The available phenolic groups on the modified film presented a good correlation with the antiradical activity toward DPPH(•). Moreover, the polymer synthesized in this work showed a good protective activity against ascorbic acid oxidation in real samples of orange juice.

Variations in bioactive substance contents and crop yields of lettuce (Lactuca sativa L.) cultivated in soils with different fertilization treatments.

Changes in crop yields and bioactive substance contents were studied in lettuce crop concerning the influence of soil nutritional status as a result of compost and vermicompost additions obtained from different organic substrates. Plant productions and main pigment contents in lettuce were higher in all the fertilized soils than in the untreated soil, with the exception of the one treated with urban solid waste compost. These positive effects correlate with nitrogen level increase in soil. However, the high saline input of this compost prepared from food home wastes interferes in lettuce growth and prevents it from being higher than the control. Marked decreases in lettuce phenolic contents and antiradical activity were found in most of the treatments. Composts and vermicomposts produced through the processing of cattle manures, agro-industrial organic wastes significantly increased lettuce crop yield enriching its pigment contents, although, in some cases, antioxidant value and phenolic levels were reduced.