Effect of Flavorization on Virgin Olive Oil Oxidation and Volatile Profile

The volatile compounds of virgin olive oil (VOO) have an important role from a sensory point of view as they are responsible for the aroma of the oil. Once the oil is obtained, auto-oxidation is the main process contributing to its deterioration, modifying the volatiles profile and aroma. The addition of aromatic herbs to VOO is a traditional technique to change the flavor and to preserve the oil. The aim of this study was to evaluate the effect on the volatile profile and sensory properties of flavoring VOO with rosemary and basil herbs and its impact on the evolution of the oxidative process during a six-month shelf-life study at 15.7 ± 3.6 °C and exposed to 500 ± 100 lx of light for 12 h each day. The determination of quality parameters, volatiles concentrations and VOO sensory properties and their comparison with the flavored VOO samples showed that the addition of basil or rosemary herbs, in addition to retarding the oxidation of the oil, allowed the discrimination of the flavored samples due to the migration of compounds from herbs to the oil. The aroma of basil olive oil (BOO) samples was mainly due to β-pinene, ocimene and 1,8-cineol compounds while for rosemary olive oil (ROO) samples, their aroma was mainly due to the concentrations of camphene, β-myrcene, α-terpinolene, limonene and 1,8-cineol. From the antioxidant standpoint, the effect of the herbs was more noticeable from the third month onwards.

Comprehensive Evaluation of Quality of Camellia semiserrata Seed Oils from Various Harvest Dates

The ripening degree of camellia fruit is one of the key factors affecting the quality of camellia seed oil. In this study, taking Camellia semiserrata as the research object, the oil content, physicochemical indexes, nutritional indexes, fatty acid composition, and volatile compounds of camellia seed oils from various harvest dates (from September to October) were determined. The results showed that with the increase of the ripening degree of camellia fruit, the oil content of camellia seed increased at first and then decreased and reached the highest (58.74%) on September 30, while the acid value, peroxide value, β-sitosterol, α-tocopherol, and polyphenols of camellia seed oil showed a downward trend. Among them, the highest contents of β-sitosterol, α-tocopherol, and polyphenols were observed on September 2, which were 6881.60, 311.34, and 78.08 mg/kg, respectively. In terms of the fatty acid composition of camellia seed oils, the content of oleic acid increased at first and then decreased, the content of linoleic acid and palmitic acid decreased gradually, while the content of stearic acid increased gradually. A total of 37 volatile compounds were identified in different samples, including 12 aldehydes, 5 ketones, 12 alcohols, 2 acids, 5 esters, and 1 other. With the increase of the ripening degree, the concentration of aldehydes and alcohols increased at first and then decreased, the concentration of ketones and esters decreased gradually, but the concentration of acid compounds had no obvious rule. In addition, the camellia seed oils from various harvest dates were classified and comprehensively evaluated by principal component analysis and grey relation analysis. The results showed that different camellia seed oils could be divided into three groups, and the comprehensive score of camellia seed oils on September 30 was the highest. In general, this work can provide theoretical guidance for the harvest date of Camellia semiserrata.