A four year study to determine the optimal harvesting period for Tunisian Chemlali olives

Abstract

Due to the importance of the stage of maturity on several olive pomological parameters and oil quality indices, and to the interest that Tunisian olive oil production has recently received, the optimal harvesting period for the main Tunisian olive cultivar, Chemlali, was assessed. For the first time, a four-season crops study, carried out in three representative geographical areas, was focused on both olive fruit pomological parameters and oil chemical composition at different stages of maturity. The stage of maturity was the factor showing the highest influence on the major part of these parameters, followed by the crop year. To guarantee a reasonable fat content and a good chemical quality of oil, in particular a harmonious acidic composition, acceptable UV absorbance, and a content high of antioxidants, unsaponifiable matter and sterols, the optimal harvesting period for Chemlali olives would appears to be between the end of November to the middle of December, which corresponds to a maturity index between 2.5 and 3.5.

Zeytinyağı Ekstraksiyon İşleminin Yanıt Yüzey Metodu ile Optimizasyonu

“…Peroxide value of oil extracted from olive fruits at purple stage was higher than that measured for black fruits (Figures 5 and 6). Peroxide value change with fruit maturity agrees with that reported by Gutiérrez et al [3], Salvador et al [6], Rotondi et al [12], Baccouri et al [7], Baccouri et al [13], Youssef et al [14] and Lazzez et al [10]. Kneading conditions (temperature and time) were also examined in the present study to investigate their influences on peroxide values of produced olive oils.…”

“…Oil yield observed in the present study agrees with that reported for Memecik cultivar by Nergiz ve Ergönül [26]. Besides of kneading conditions, maturity of olive fruit has been reported to be effective on oil yield [1][2][3][4][5][6][7][8][9][10][11]. Models produced by response surface methodology were given in Table 3.…”

“…Being agree with our results, Finotti et al [4], Salvador et al [6], Rotondi vd. [12], Baccouri et al [7], Baccouri et al [13], Youssef et al [14] and Lazzez et al [10] reported that free acidity of oil depends on maturity of olive fruits. Temperature and time dependence of free acidity are shown in Figures 3 and 4 for oils produced from purple and black fruits, respectively.…”

“…At this point it should be noted that the percentage of oil in fresh olive fruit continuously increases as fruit ripens. This favourable effect of the maturity on olive oil yield is well documented and it is attributed to the decrease in moisture content with increasing maturity [1][2][3][4][5][6][7][8][9][10][11]. Additionally free acidity increases and the peroxide value decreases depending on an increase in maturity index [3,4,6,7,10,[12][13][14].…”

Transcriptomics and Biochemical Profiling: Current Dynamics in Elucidating the Potential Attributes of Olive

“…On the other hand Yousfi et al (2012) found that VOO extracted from mechanically harvested fruit of Arbequina retains chemical composition and best quality at 3 o C. Hence, mechanical harvesting hinders the deterioration process and increases the shelf life of olive fruits. The nutritional and organoleptic aspects of VOO are based upon phenolics, therefore, to gain a product of economic worth it is important to understand the origin of enzymatic activities undermining phenols metabolism during fruit storage period (Lazzez et al, 2011). Thus, it is important to understand basic biochemistry and molecular dynamics of olive fruit and oil for making its better commercialization in international markets.…”