The changes in ripe olive fat produced by processing were studied according to cultivars using the general linear model, principal component analysis (PCA), predictive discriminant analysis (DA), and hierarchical clustering. Acidity, peroxide value, K(270), and DeltaK increased during storage. Acidity also increased after sterilization, whereas K(270) decreased after darkening; K(232) showed a progressive decrease during processing. Fatty acids (except C17:0, C18:0, and C24:0), triacylglycerols (except PLLn, OOLn+PoOL, PLL+PoPoO, SOO, and POS+SLS), polar compounds, diacylglycerol, and monoacylglycerols also suffered statistically significant changes during processing. A PCA discriminated between cultivars and, within the same cultivar, among the raw materials from the rest of the treatments. Using fatty acid and triacylglycerol compositions, predictive DA discriminated between cultivars (100% correct), but high discriminant capacity among processing steps (95% correct assignation and 87% in cross-validation) was achieved only with fatty acids. A hierarchical clustering analysis successfully grouped cultivars and processing steps according to overall olive oil composition and quality.
21The volatile profiles of Spanish-style green table olives elaborated with Manzanilla,
22Gordal and Hojiblanca cultivars grown at different locations in Spain were established 23 by solid phase micro-extraction (SPME) and gas chromatography coupled to mass 24 spectrometry (GC-MS). A total of 102 volatile compounds were identified, belonging to 25 distinct chemical classes, and 20 of them are reported for the first time in table olives.
26The headspace profile was predominated by alcohols and phenols, followed by acids 27 and esters, whereas the relative amounts of the remaining classes were quite lower (< 28 5% in general). The principal compounds characterizing the headspace for most samples
The aim of the present study was to assess the malodorous spoilages of Spanish-style green table olives through microbial and metabolite composition using current measuring techniques (e.g., high-throughput DNA sequencing, headspace solid-phase microextraction combined with gas chromatography-mass spectrometry). Under different alkaline and washing conditions, the spoilage fermentations were reproduced with Gordal and Manzanilla olive cultivars using a low salt concentration (71 g L−1 NaCl) in the initial brine. The degradation of lactic acid and significant increases in volatile fatty acids and phenols were found in all the spoiled samples in comparison with the unspoiled control samples. According to high-throughput DNA sequencing, Cardiobacteriaceae and Ruminococcus were the dominant bacteria in the spoiled samples. PLS regression and Pearson’s correlation coefficient analyses revealed positive and negative correlations among microbial communities, metabolites, and sensory spoilage descriptors. Notably, the “zapatera” descriptor was significantly associated with Propionibacterium, which was positively correlated with acetic acid, propionic acid, succinic acid, and methyl propanoate; while the “butyric” descriptor exhibited a significant positive relationship with the genus Ruminococcus, which gave an almost significant correlation with propionic and butyric acids.
This work supplies information on the lipids, unsaponifiable matter, sterols, and fatty and triterpenic alcohols in table olives. The mean lipid contents, unsaponifiable values, concentration of sterols and total alcohols (aliphatic and triterpenic alcohols) were 16.15 g/ 100 g edible portion (e.p.), 4.53 g/100 g lipid, 28.68 mg/ 100 g e.p. and 13.28 mg/100 g e.p., respectively. The overall mean content of cholesterol was 0.5 mg/100 g e.p., with a minimum of 0.08 mg/100 g e.p. in Manzanilla olives stuffed with ''piquillo'' pepper, and a maximum of 4.9 mg/100 g e.p. in Manzanilla olives stuffed with marinated anchovy strips. Table olives contain higher concentrations of phytosterols than olive oil. The chemometric analysis showed that lipids, unsaponifiable matter, sterols, and fatty and triterpenic alcohol contents in table olives were slightly affected by processing and that some misclassification was possibly related to maturation. There were also noticeable differences between cultivars.
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