Production and characterisation of reduced-fat and PUFA-enriched Burrata cheese.

Burrata is an Italian fresh 'pasta filata' cheese made from cow's milk and cream that is rapidly spreading in Europe. It has very high caloric content, and a technological protocol was developed for producing a reduced-fat type and fortifying it with polyunsaturated fatty acids (PUFA) of vegetable origin. A satisfactory reduced-fat prototype was obtained by using a 14% fat cream, which was specifically developed by diluting double cream with a suspension of carob seed flour. The composition of the new cheese changed with respect to the control, but the sensory characteristics were not impaired. Moisture increased from 62·6 to 68·4%, fat on dry matter decreased from 59·1 to 34·7%, and the caloric content decreased from 1060·8 to 718 J/100 g. Proteolysis and lipolysis were not affected by the technological modifications: after 7 d storage, the electrophoretic pattern of caseins and the free fatty acids profile of experimental and control cheeses were not significantly different. Fortification of reduced-fat Burrata with PUFA was obtained by using two commercial formulates available at a compatible price with the current economic values of the cheese. The two formulates derived from flaxseeds and Carthamus tinctorius oil and allowed enrichment in C18 :3 : n3 (α-linolenic acid, ALA), and 9cis,11trans- and 10trans,12cis- conjugated linoleic acid (CLA), respectively. Fortification was easy to perform under a technical point of view, but the negative sensory impact limited fortification at a maximum of 7·0 mg g-1 fat ALA and 6·8 g-1 fat CLA.

Influence of some packaging materials and of natural tocopherols on the sensory properties of breakfast cereals.

The combined effect of natural antioxidants and packaging materials on the quality decay of breakfast cereals during storage was evaluated. Corn flakes were produced on industrial scale, using different packages and adding natural tocopherols to the ingredients, and stored for 1 year. The samples were then submitted to sensory analysis and HS-solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) analysis. The packaging had a significant influence on the sensory profile of the aged product: metallized polypropylene gave the highest levels of oxidation compounds and sensory defects. The sensory profile was improved using polypropylene and especially high-density polyethylene. Natural tocopherols reduced the sensory decay of the flakes and the oxidative evolution of the volatile profile. They gave the most remarkable improvement in polypropylene (either metallized or not) packs. Polypropylene showed a barrier effect on the scalping of volatiles outside of the pack. This led to higher levels of oxidation volatiles and faster rates of the further oxidative processes involving the volatiles.

Vacuum-packed ripened sausages: evolution of volatile compounds during storage.

BACKGROUND: Various studies have shown the ability of volatile compounds to influence the quality of charcuterie products because of their effect on sensorial properties. To the best of our knowledge, there are no data in the scientific literature concerning the evolution of volatile compounds of vacuum-packed ripened sausages over time. The aim of this work was to evaluate the evolution of volatile compounds in vacuum-packed ripened sausages over time, considering that this kind of packaging is the most commonly used to prolong the shelf-life of these products. RESULTS: Sixty-nine volatile compounds were identified. Those derived from spices represented the prevailing compounds at the beginning of storage and significantly decreased (P<0.001) during 5 months of storage, as a result of the well-known antioxidant activity. Conversely, compounds derived from the autoxidation of lipids, which are among those chiefly responsible of sensorial properties of meat products, significantly increased (P<0.001). CONCLUSION: The research demonstrated that vacuum packaging influenced the evolution of volatile compounds during storage of ripened sausages. In particular, the increase of volatile compounds derived from autoxidation of the lipid fraction indicated that oxidative processes involved the fatty fraction of ripened sausages also in the scarcity of oxygen.

Effects of monoacylglycerols on the oxidative stability of olive oil.

BACKGROUND: The study of pro- and anti-oxidant compounds is important for their influence on the shelf-life and nutritional value of food. The aim of this research was to evaluate the activity of monoacylglycerols (MAG), obtained by partial saponification of a purified olive oil, added in increasing amounts to the same oil and submitted to the Rancimat test and oven test at 60 °C. Besides routine analyses, high-performance size exclusion chromatography analysis of polar compounds was performed. RESULTS: The addition of MAG led in all cases to a significant slowdown of the oxidative processes. These trends were more evident as the oxidation went on. The purified oil added with 30 g kg(-1) of MAG after 9 days of oven test at 60 °C presented a level of oxidative degradation significantly lower than the control after only 4 days. CONCLUSION: The data showed a marked antioxidant effect of MAG in purified olive oil, contrary to what has been observed by other authors, who noticed either a pro-oxidant or a non-antioxidant activity of these compounds in soybean oil. A different behaviour of MAG during oxidation could depend on the different fatty acid composition of the oil matter they are added to.

Effect of infusion of spices into the oil vs. combined malaxation of olive paste and spices on quality of naturally flavoured virgin olive oils.

Olive oil flavouring with aromatic plants and spices is a traditional practice in Mediterranean gastronomy. The aim of this work was to compare the influence of two different flavouring techniques (infusion of spices into the oil vs. combined malaxation of olives paste and spices) on chemical and sensory quality of flavoured olive oil. In particular, oxidative and hydrolytic degradation (by routine and non-conventional analyses), phenolic profiles (by HPLC), volatile compounds (by SPME-GC/MS), antioxidant activity, and sensory properties (by a trained panel and by consumers) of the oils were evaluated. The obtained results evidenced that the malaxation method was more effective in extracting the phenolic compounds, with a significantly lower level of hydrolysis of secoiridoids. As a consequence, antioxidant activity was significantly lower in the oils obtained by infusion, which were characterized by a higher extent of the oxidative degradation. The volatile compounds were not significantly influenced by changing the flavouring method, apart for sulfur compounds that were more abundant in the oils obtained by the combined malaxation method. From a sensory point of view, more intense bitter and pungent tastes were perceived when the infusion method was adopted.

Fate of oxidized triglycerides during refining of seed oils.

The evolution of oxidized triglycerides (ox-TG) during industrial refining was studied in soybean, sunflower, peanut, and corn oils. The analytical techniques used were silica gel column chromatography and high-performance size exclusion chromatography. The decrease in ox-TG during refining (42.3% on average) was accompanied by an increase in triglyceride oligopolymers (TGP). The inverse correlation between the two lipid groups suggests that the decrease in ox-TG during refining was due in part to the occurrence of polymerization reactions. An inverse correlation was also found between the percentage sum of ox-TG + TGP and percent TGP, indicating that a part of the ox-TG also underwent degradation or transformation reactions. On average, almost 58% of the ox-TG remained unchanged during refining and, of the rest, about half was involved in polymerization reactions and half in degradation or transformation reactions.

Improving virgin olive oil quality by means of innovative extracting biotechnologies.

Three major virgin olive oil varieties (Dritta, Leccino, and Coratina) extracted by a modern centrifugation system aided with a new plant enzyme preparation (having prevalently pectolytic activity) were characterized. These oils showed a clearly enhanced quality standard, owing to higher levels of some important minor components (phenolics, volatiles, tocopherols, carotenes, and chlorophylls) and to frequently lower concentrations of oxidized triglycerides and diglycerides. The oils were therefore characterized by lower susceptibility to oxidation and longer shelf life, and their flavor, aroma, and color features appeared to be significantly improved. The saponifiable fraction was practically not affected as the enzymatic effects involved only the membranes of the oil droplets, where the nonglyceridic compounds are essentially located.

Complex role of monoacylglycerols in the oxidation of vegetable oils: different behaviors of soybean monoacylglycerols in different oils.

The relationship between fatty acid composition of oils and their oxidative stability in the presence of monoacylglycerols was investigated. Purified vegetable oils were added at increasing amounts (0.5, 1, 2, and 3%) of monoacylglycerols obtained from purified soybean oil and submitted to an oven test (60 °C for 18 days). The obtained results showed a generally antioxidant effect of monoacylglycerols, with remarkable differences among oils. The antioxidant effect was significantly higher in less unsaturated oils, such as palm and olive oils. Among the more unsaturated vegetable oils, peanut and sunflower oils showed an almost linear slowdown of oxidation, slightly less pronounced in sunflower oil, which was the most susceptible to oxidation due to its high content of linoleic acid. A peculiar trend was highlighted for soybean oil, where the antioxidant effect of high amounts of monoacylglycerols was opposed to a pro-oxidant effect observed up to 1%.

Traceability of Italian Protected Designation of Origin (PDO) table olives by means of microsatellite molecular markers.

The aim of this work was to develop a DNA microsatellite-based method of analysis to allow traceability of the three Italian Protected Designation of Origin (PDO) table olives in comparison with fruits of another seven highly diffused table olive cultivars. The analyses were carried out by using 16 primer pairs, with a mean of five different alleles detected per primer set, and power of discrimination from 0.56 to 0.90. Allelic error rates in the range of 0-3.8% were observed. By combining data from the most reliable and highly informative microsatellites (DCA3, DCA16, DCA17, DCA18, UDO-043, and GAPU101), it was possible to identify the PDO fruits over the panel of 10 cultivars, with the probability of a chance match between different cultivars as low as 10(-9) and with 0.5% error rate. The amplification profile is independent of environmental and processing conditions and is helpful to verify the authenticity of PDO samples.

Diacylglycerol isomers in extra virgin olive oil: Effect of different storage conditions.

An experimental investigation was carried out with the aim to investigate on the isomerisation of 1,2-diacylglycerols to 1,3-diacylglycerols as a function of the storage conditions, as well as to identify indices useful to evaluate the freshness of the oils. Two oils derived from two different cultivars (Coratina and Ogliarola barese) were stored for two years as follows: in bottles at dark; in clear glass bottles at light; in green glass bottles at light; in bottles at dark, the latter subjected to repeated opening and samplings to simulate domestic use. The obtained results evinced that during the storage period a significant increase in the 1,3-isomers was observed due to an isomerisation from the 1,2 to the 1,3 isomeric form, consequently the 1,3/1,2 ratio increased in both oils. The covariance analysis of the data showed that the isomerisation of diacylglycerols, taking place during time, was affected by the type of oil, probably due to the different initial hydrolysis level, but was not affected by the storage conditions. Among the parameters considered, the total diacylglycerols/1,3-diacylglycerols ratio could be used as freshness index of extra virgin olive oil, since it is not affected by either oil or storage conditions.

Influence of the thermal stabilization process on the volatile profile of canned tomato-based food.

The literature contains several papers dealing with the volatile constituents contributing to the aroma of fresh and processed tomatoes. Along with the traditional tomato-based products, tomato-based pâtés, characterized by complex ingredient formulations, are commonly consumed as a seasoning for pasta, and as a dressing for meats, salads, and sandwiches. To the best of our knowledge, no investigations have been published on the influence of thermal stabilization treatments on the composition of volatile compounds in tomato-based pâtés. To this aim, thermally stabilized and not stabilized tomato-based pâtés were subjected to the analysis of volatile compounds. The results obtained highlighted the influence of the thermal stabilization process on the evolution of volatile composition tomato-based pâtés. In particular, the terpenic compounds showed significant decreases after the thermal stabilization process treatment, due to their degradation and oxidation favored by high temperatures. The thermal stabilization caused, moreover, an increase in volatile compounds deriving from lipid oxidation and Maillard reaction, characterized by low-sensory thresholds, and from the thermal degradation of carotenoids and fresh tomato-derived compounds.

Effect of the type of oil on the evolution of volatile compounds of taralli during storage.

Baking process leads to a huge quantity of newly formed volatile compounds, which play a major role in developing the flavor of the final product. The aim of this work was to investigate on the evolution of the volatile profile of taralli as a function of both the kind of oil used in the dough and the storage time. The volatile compounds from the taralli were extracted by headspace solid-phase microextraction and analyzed by gas-chromatography/mass spectrometry (GC/MS). Forty-four volatile compounds were identified in taralli, most of which produced by thermically induced reactions occurring during baking process, such as volatiles deriving from Maillard reaction and/or sugar degradation and lipid oxidation. The results obtained demonstrated the essential role played by the type of oil on the formation and on the release of volatile compounds. The volatile compounds significantly increased during storage and their individual levels were in most cases significantly lower in taralli made with extra virgin olive oil than in those made with refined oils. Finally, the taralli made with extra virgin olive oil, compared with those prepared with other vegetable oils, showed to be more resistant to oxidation, probably due to the presence of natural antioxidants.

Influence of the different oils used in dough formulation on the lipid fraction of taralli.

An experimental investigation was carried out to evaluate the quality of taralli as a function of the type of oil used in their dough formulation. To this end, 4 types of oil (extra virgin olive oil, olive oil, olive-pomace oil, and refined palm oil) were utilized to prepare taralli to investigate on the lipid fraction degradation and evaluate the taralli acceptability by consumers. The data obtained pointed out that taralli manufactured with extra virgin olive oil were significantly more appreciated than those made with refined oils due to their visual appearance and odor. Moreover, with respect to the other kinds of oil, the use of extra virgin olive oil led to significantly lower values (P < 0.05) of specific absorption at 232 and 270 nm (K(232) and K(270) , respectively) and of triacylglycerol oligopolymers. It also proved to present a much lower content in oxidized triacylglycerols and diacylglycerols than olive-pomace oil and refined palm oil, respectively. Furthermore, trans fatty acid isomers were absent in taralli made with extra virgin olive oil but were constantly present in those produced with refined oils.

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.

Evolution of the volatile compounds of ripened sausages as a function of both storage time and composition of packaging atmosphere.

An experimental investigation was carried out to study the evolution of the volatile compounds of ripened sausages as a function of both storage time (time) and composition of packaging atmosphere (MAP). Ripened sausages, prepared at an industrial plant, were packed applying three different atmosphere compositions and were stored for three months. The obtained data evinced that the evolution of the volatile compounds was significantly related to the variable time more than to the variable MAP. The main volatile compounds were those derived from spices. Among them, Δ3-carene was the most abundant and a significant decrease was observed during storage (p<0.05). The volatile compounds derived from lipid autoxidation showed generally a significant increase during storage, suggesting the raise of lipid oxidation also at low oxygen concentration. Moreover, octanal and nonanal were significantly influenced by the atmosphere composition, with the highest values in samples packed at the lowest CO2 concentration.

Influence of processing and storage time on the lipidic fraction of taralli.

An experimental investigation was carried out to evaluate the influence of processing and storage time on the lipidic fraction of taralli. The data obtained pointed out that the kneading phase caused a significant increase of the oxidized triacylglycerols and triacylglycerol oligopolymers, primary and secondary oxidation compounds, respectively, accompanied by a significant decrease of the content of polyunsaturated fatty acids. The successive baking step caused the degradation of a part of the oxidized compounds to volatile substances, as confirmed by the p-Anisidine values, whereas the storage time determined a further significant increase of the level of oxidized triacylglycerols. Finally, the level of diacylglycerols, monoacylglycerols, and free fatty acids, indicative of hydrolytic degradation, did not show significant changes. The principal component analysis allowed one to clearly distinguish among samples obtained through processing conditions.