Sequential Biorefining of Bioactive Compounds of High Functional Value from Calafate Pomace (Berberis microphylla) Using Supercritical CO2 and Pressurized Liquids.

A biorefinery process was developed for a freeze-dried pomace of calafate berries (Berberis microphylla). The process consisted of extraction of lipophilic components with supercritical CO2 (scCO2) and subsequent extraction of the residue with a pressurized mixture of ethanol/water (1:1 v/v). scCO2 extracted oil from the pomace, while pressurized liquid extraction generated a crude extract rich in phenols and a residue rich in fiber, proteins and minerals. Response surface analysis of scCO2 extraction suggested optimal conditions of 60 °C, 358.5 bar and 144.6 min to obtain a lipid extract yield of 11.15% (d.w.). The dark yellow oil extract contained a good ratio of ω6/ω3 fatty acids (1:1.2), provitamin E tocopherols (406.6 mg/kg), and a peroxide index of 8.6 meq O2/kg. Pressurized liquid extraction generated a polar extract with good phenolic content (33 mg gallic acid equivalents /g d.w.), anthocyanins (8 mg/g) and antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl test = 25 µg/mL and antioxidant activity = 63 µM Te/g). The extraction kinetics of oil by scCO2 and phenolic compounds were optimally adjusted to the spline model (R2 = 0.989 and R2 = 0.999, respectively). The solid extracted residue presented a fiber content close to cereals (56.4% d.w.) and acceptable values of proteins (29.6% d.w.) and minerals (14.1% d.w.). These eco-friendly processes valorize calafate pomace as a source of ingredients for formulation of healthy foods, nutraceuticals and nutritional supplements.

Obtaining an Oily Ingredient Rich in PUFAS and Tocopherols and a High-Nutritional-Value Flour from Beans (Phaseolus vulgaris L.) by Supercritical CO2 Extraction.

The objective of this work was to carry out a preliminary study of the fractionation by supercritical CO2 (sc-CO2) extraction of two varieties of Peruvian beans (Phaseolus vulgaris L.), white (WB) and red (RB), to obtain two novel products: an oil rich in essential fatty acids and tocopherols and a defatted flour with high nutritional value and amino acids. The extraction temperature and pressure were optimized using the response surface methodology (RSM) and the extraction kinetics were optimized using the Spline equation. The results revealed that the best extraction conditions for WB and RB were 396.36 Bar, 40.46 °C, with an efficiency of 1.65%; and 391.995 Bar, 44.00 °C, with an efficiency of 1.12%, respectively. The WB and RB oils presented a high degree of polyunsaturation (63.2 and 52.8%, respectively), with oleic, linoleic, and linolenic fatty acids prevailing. Gamma-tocopherol was the predominant antioxidant in both oils. The residual flours (WB and RB) obtained after extraction with sc-CO2 had a high average content of proteins (23%), carbohydrates (61%), and minerals (3%). The limiting amino acids of WB were: Fen + Tyr, Leu, Lys, and in RB, only Leu was limiting. The viscosity of the solutions (20%) of the WB and RB flours mainly adjusted to the Waele's Ostwald model (r = 0.988). It is concluded that both products (oil and bean flour) obtained in an optimized manner using an eco-friendly technology with sc-CO2 have high nutrient and bioactive component content and can be used in the development of new ingredients and healthy foods of plant origin.

Heat sensitization of Escherichia coli by the natural antimicrobials vanillin and emulsified citral in blended carrot-orange juice.

Efforts have been focusing on the way to overcome the impact of heating on food quality while achieving the desired shelf life. In this sense, the thermosensitization of E. coli using the natural antimicrobials vanillin (V; 0.8 and 1.0 g/L) or/and emulsified citral (C; 0.012 and 0.025 g/L) was assessed at 58 and 60 °C in blended carrot-orange juice (pH 4.0; 9.0°Brix). All combined treatments exceeded the inactivation achieved by the single thermal treatments in half the time. The inactivation of the binary treatments (V or C + heating) at 58 °C was 3.84-0.62 log-cycles more effective than the control, particularly with vanillin. Ternary treatments (V + C + heating) at 58 °C increased the microbial reduction approximately 30%; however, at 60 °C no further inactivation was observed, suggesting the thermal effect prevailed. This was verified by the higher b Weibullian parameter and the narrower frequency distributions. The selected treatments 1.0 V + 0.012C at 58 and 60 °C were challenged against the pathogenic E. coli O157:H7 and found to be effective. Additionally, the microbiota of the juice was maintained at acceptable levels during storage (4 °C). In conclusion, there was an increase in the heat sensitivity of E. coli due to the natural antimicrobials, particularly vanillin at 58 °C. Therefore, reducing the intensity of the thermal processing will lead to clean label, high-quality juices, while addressing food safety requirements.

Rheological and Structural Study of Salmon Gelatin with Controlled Molecular Weight.

This study explores the molecular structuring of salmon gelatin (SG) with controlled molecular weight produced from salmon skin, and its relationship with its thermal and rheological properties. SG was produced under different pH conditions to produce samples with well-defined high (SGH), medium (SGM), and low (SGL) molecular weight. These samples were characterized in terms of their molecular weight (MW, capillary viscometry), molecular weight distribution (electrophoresis), amino acid profile, and Raman spectroscopy. These results were correlated with thermal (gelation energy) and rheological properties. SGH presented the higher MW (173 kDa) whereas SGL showed shorter gelatin polymer chains (MW < 65 kDa). Raman spectra and gelation energy suggest that amount of helical structures in gelatin is dependent on the molecular weight, which was well reflected by the higher viscosity and G' values for SGH. Interestingly, for all the molecular weight and molecular configuration tested, SG behaved as a strong gel (tan δ < 1), despite its low viscosity and low gelation temperature (3-10 °C). Hence, the molecular structuring of SG reflected directly on the thermal and viscosity properties, but not in terms of the viscoelastic strength of gelatin produced. These results give new insights about the relationship among structural features and macromolecular properties (thermal and rheological), which is relevant to design a low viscosity biomaterial with tailored properties for specific applications.

Hyaluronidase inhibiting activity and radical scavenging potential of flavonols in processed onion.

The flavonol content and anti-inflammatory and antioxidant activities of onion treated by high-pressure processing (HPP) and HPP combined with freeze-drying and pulverization (HPP-FD-P) were evaluated. Allium cepa L. var. cepa, 'Recas' was treated at T1 (200 MPa/25 °C/5 min), T2 (400 MPa/25 °C/5 min), and T3 (600 MPa/25 °C/5 min). After treatment, HP-treated and untreated samples were frozen (diced onion, HP-treated). Subsequently, part of the diced samples was freeze-dried and pulverized (pulverized onion, HP-treated and freeze-dried). Flavonol content and anti-inflammatory and antioxidant activities (hyaluronidase inhibiting activity, NO(•), ABTS(•+), and DPPH(•) scavenging capacity, ferric reducing antioxidant power, and antioxidative capacity by photochemiluminescence) were measured in nonhydrolyzed and hydrolyzed extracts. Hydrolysis was carried out in order to evaluate the effect of HPP and HPP-FD-P on both anti-inflammatory and antioxidant activities of extracts mainly containing aglycone forms. HPP-FD-P increased quercetin 3,4'-diglucoside, quercetin 4'-glucoside, quercetin 3-glucoside, and isorhamnetin 3,4'-diglucoside extractability. The present study suggests that HPP (especially treatment at 400 MPa) and HPP-FD-P may be of benefit for obtaining functional ingredients from onion, as suggested by increased NO(•) scavenging capacity and maintenance of the antioxidant activity mainly in hydrolyzed extracts.