Francesco Caponio

Phenolic compounds of virgin olive oil: influence of paste preparation techniques

An experimental investigation was carried out on olive oils of the Ogliarola Salentina and Coratina cultivars to assess the influence of the two different olive grinding techniques and kneading process on the quality of the oils. The experimental data obtained showed that resistance to oxidation, total phenols and phenolic compounds analysed for HPLC were higher in the Coratina oils than in the Ogliarola oils. The use of hammer-crushers plus kneader rather than stone mills plus kneader always produced significant increases in the total phenols. Resistance to oxidation was assessed by the Rancimat method and showed a significant correlation with the amounts of total phenols and of an unidentified substance (peak I) which was conspicuously present amongst the substances evaluated for HPLC.

Effect of vacuum-packaging storage on the quality level of ripened sausages.

To investigate the influence of vacuum-packaging on both the sensory properties and the degradation level of their lipid fraction, some ripened sausages (30 days) were further stored for 40 days under vacuum-packaging and compared to sausages kept unpackaged for the same period of time. The same kind of sausages was used in both the trials. As for the sensory properties, after storage the unpackaged sausages showed significantly higher mean scores of red intensity and global flavour than vacuum-packed ones (p<0.01 and p<0.05, respectively) indicating a brighter red colour of meat and a greater overall appreciation by the panelists. Regarding the degradation of the lipid fraction, significantly higher values (p<0.01) of the free fatty acids were detected in the vacuum-packed samples, indicating a greater hydrolytic degradation of their lipid fraction as compared to the sausages stored unpackaged. The oxidative degradation of the fatty fraction, measured by the combined use of conventional (determination of peroxide value and TBA test) and non-conventional techniques (HPSEC analysis of the polar compounds of the lipid fraction) showed significant increases during storage for both the storage conditions considered but no significant differences were found between packaged and unpackaged sausages.

Production and characterization of functional biscuits obtained from purple wheat.

Purple wheat contains higher levels of anthocyanins than conventional wheat cultivars. The aim of this work was to produce anthocyanin-rich biscuits from purple wheat, and to characterize the final product. Control biscuits, having the same formulation but obtained from a non-pigmented wheat cultivar, were used for comparisons. Purple biscuits showed a level of total anthocyanins of 13.86 mg/kg cyanidin 3-O-glucoside and exhibited higher antioxidant activity than control. The volatile compounds profile of purple biscuits showed lower levels of lipid-derived carboxylic acids and higher levels of alcohols and aldehydes than control biscuits, indicating a lower oxidative degradation of the lipid fraction. In particular, the ratio (lipid-derived alcohols+aldehydes)/acids accounted for 5.9 in purple and 3.0 in control biscuits. The sensory score for friability and the spread ratio of purple biscuits accounted for 2.6 and 6.0, respectively.

Towards green analysis of virgin olive oil phenolic compounds: Extraction by a natural deep eutectic solvent and direct spectrophotometric detection.

The determination of phenolic compounds in extra virgin olive oils (EVOO) by means of rapid, low-cost, environment-free methods would be a desirable achievement. A natural deep eutectic solvent (DES) based on glucose and lactic acid was considered as extraction solvent for phenolic compounds in EVOO. DESs are green solvents characterized by high availability, biodegradability, safety, and low cost. The spectrophotometric characteristics of DES extracts of 65 EVOO samples were related to the total phenolic content of the oils, assessed by methanol-water extraction coupled to the Folin-Ciocalteu assay. A regression model (ncalibration=45, nvalidation=20), including the absorbance at two wavelengths (257, 324nm), was obtained, with an adjusted R(2)=0.762. Therefore the DES could provide a promising and viable approach for a green screening method of phenolic compounds in EVOO, by means of simple spectrophotometric measurements of extracts, even for on-field analysis (for example in olive mills).

Functional, textural and sensory properties of dry pasta supplemented with lyophilized tomato matrix or with durum wheat bran extracts produced by supercritical carbon dioxide or ultrasound

A study was carried out to produce functional pasta by adding bran aqueous extract (BW) and bran oleoresin (BO) obtained using ultrasound and supercritical CO2, respectively, or a powdery lyophilized tomato matrix (LT). The bioactive compounds, hydrophilic and lipophilic antioxidant activity (HAA and LAA) in vitro, were evaluated. BW supplementation did not improve antioxidant activity, whilst LT pasta showed unconventional taste and odor. BO pasta had good levels of tocochromanols (2551μg/100g pasta f.w.) and carotenoids (40.2μg/100g pasta f.w.), and the highest HAA and LAA. The oleoresin altered starch swelling and gluten network, as evidenced by scanning electron microscopy, therefore BO pasta had structural characteristics poor compared with the control (4.8% vs. 3.2% cooking loss), although this difference did not affect significantly overall sensory judgment (74 vs. 79 for BO and control, respectively). BO supplementation was most effective for increasing antioxidant activity without jeopardizing pasta quality.

Vacuum-packed ripened sausages: evolution of oxidative and hydrolytic degradation of lipid fraction during long-term storage and influence on the sensory properties.

An experimental investigation was carried out with the aim to understand the oxidative and hydrolytic phenomena involving the lipid fraction of vacuum-packed sausages during long-term storage (5 months) and to verify their influence on the sensory characteristics. The data obtained pointed out that the oxidation was more pronounced in the initial stages of storage than in the further period, while the hydrolysis of lipid fraction significantly advanced during the whole storage time, supported by the high moisture level of the product. Both these phenomena resulted to be correlated with the sensory decay of the product. In particular, in the first stage of vacuum storage overall acceptability was found to be negatively correlated (p<0.05) with rancid taste, acid value, and oxidized triacylglycerols. In the further stage the oxidative processes slowed down and affected in a lesser extent the sensory properties, which were more distinctly characterized by the onset of pungent perception attributed to compounds arising from multiple origins such as carbohydrate fermentation. This investigation confirmed the unreliability of thiobarbituric acid reactive substances test and the usefulness of high performance size exclusion chromatography analysis of the polar compounds of the lipid fraction to correctly determine the levels of the oxidative and hydrolytic degradation of the lipid fraction of vacuum-packed ripened sausages during long-term storage.

Gluten-Free Bread Making Trials from Cassava (Manihot Esculenta Crantz) Flour and Sensory Evaluation of the Final Product

The aim of this work was to evaluate the effectiveness of the use of cassava flour in bread making, and the sensory acceptability of the final product. Different baking trials were carried out by using egg white and extra-virgin olive oil, in consideration of their high nutritional value with respect to other food additives (i.e., hydrocolloids). Significant (p < 0.05) improvements of loaf specific volume (from 2.24 to 3.93 mL/g) and crumb firmness (from 9.14 to 4.67 N) were achieved by contemporarily including egg white and extra-virgin olive oil in the formulation. Cassava breads containing both these ingredients obtained the best scores from panelists for all the test breads examined and resulted attractive as the wheat bread prepared as reference.

Evaluation of the Technological Characteristics and Bread-Making Quality of Alternative Wheat Cereals in Comparison with Common and Durum Wheat

The growing sensibility toward those foods that are characterized by natural and healthy features has raised the interest toward alternative wheat cereals. This research was carried out to compare the technological characteristics and the bread-making quality of Khorasan wheat, type Kamut and spelt (cv. Forenza), to those of common (cv. Rio) and durum wheat (cv. Norba). The results obtained show that both Forenza and Kamut gave an acceptable bread-making performance. A certain variability affected flour characteristics (protein content, carotenoid pigments and alveograph indices) over the 2 years of experimentation, due to environmental effects. This reflected on the corresponding breads but the statistical analysis indicated that, on the whole, Kamut bread was characterized by a high content of carotenoid pigments. Regarding sensory properties (profiled by means of 11 descriptors of visual appearance, texture, odor and flavor) and loaf volumes, breads from Forenza and Kamut appeared different from each other but similar to those obtained from Rio and Norba grown in the same environment, respectively.

Non-conventional parameters for quality evaluation of refined oils with special reference to commercial class olive oil

Forty olive oil samples (refined olive oil plus virgin olive oil) were tested to check the possibility of using recent non-conventional analytical parameters to assess quality. The routine analyses prescribed by the EEC Reg. No 2568/91 and subsequent extensions were carried out on all samples. The analytical techniques used included silica gel column chromatography for the separation of polar compounds from oil, and their subsequent high performance size-exclusion chromatography (HPSEC) analysis to quantify the oxidation, polymerisation and hydrolysis product classes. Based on the results obtained, it seems logical to use the percent oligopolymer content to measure the level of oxidation in commercial class olive oil. The diglyceride level can provide information about the extent of hydrolytic degradation.

Effect of Olive Oil Phenolic Compounds and Maltodextrins on the Physical Properties and Oxidative Stability of Olive Oil O/W Emulsions

The aim of this work was to study the physical properties and oxidative stability of model olive oil-in-water (o/w) emulsions stabilised by β-lactoglobulin (BLG), enriched with olive phenolic compounds, namely oleuropein, tyrosol and hydroxytyrosol, and added with maltodextrins (MD 7.5–9.9) in different concentrations to modify the viscosity of the continuous water phase. Emulsions were characterized for their viscosity, droplet size distribution, microstructure and interfacial protein coverage. The oxidative stability was monitored by means of hydroperoxides, hexanal and nonanal contents as indices of primary and secondary oxidation products, respectively. At high concentrations, MD increased significantly the viscosity of the emulsions; conversely, the addition of olive phenolic compounds did not show any significant effect on it. Both MD and phenolic compounds resulted to affect both the droplet size and the bigger to smaller particles ratio, with phenolic compounds generally improving the dispersion degree. A delay in the decomposition of hydroperoxides was observed as a consequence of MD addition, which also resulted to affect the efficiency of the phenolic compounds among the different systems. However, the highest protection towards oxidations was obtained when hydroxytyrosol was added. MD effect was related not only to the higher viscosity of the emulsions but also to complex interactions that occurred among the different components of the system.