The contents of total phenolic compounds, flavonoids, and phenolic acids were determined in selected garlic cultivars grown at four locations. The total phenolic content varied from 3.4 mg gallic acid equivalents (GAE)/g of dry matter (dm) to 10.8 mg GAE/g of dm with a mean value of 6.5 mg GAE/g of dm. The myricetin, quercetin, kaempferol, and apigenin flavonoids were not detected in any of the samples. Caffeic acid and ferulic acid were the major phenolic acids found with mean values of 2.9 mg/kg of dm and 2.6 mg/kg of dm, respectively. The mean contents of vanillic, p-hydroxybenzoic, and p-coumaric acids were comparable (0.4-0.8 mg/kg of dm), and the level of sinapic acid was negligible (< 0.1 mg/kg of dm). There was a significant effect of location but an insignificant effect of genotype on contents of caffeic, vanillic, p-hydroxybenzoic, and p-coumaric acids. However, genotype but not location affected the contents of total phenolics and ferulic acid. On average, the white garlic cultivars and Chinese garlic cultivars contained higher contents of total phenolics and ferulic acid than the purple garlic cultivars. However, the differences in the total phenolic content between the purple and white garlic cultivars were not significant.
The presence of acrylamide was investigated in different presentations of commercial black ripe olives, a well-known sterilized alkali-treated product. The analysis was performed by gas chromatography-mass spectrometry (GC-MS) after bromination of acrylamide, using (13C3)acrylamide as internal standard. In-house validation data for commercial ripe olives showed good precision and accuracy of the method, with repeatability below 3% and recoveries between 94 and 105%. Acrylamide was detected in all samples, but its concentration varied significantly from 176 to 1578 microg/kg of pulp. The effects of different processing conditions (two preservation methods and three darkening methods), cultivar (Hojiblanca or Manzanilla), and presentation form (pitted or sliced olives) on acrylamide content were evaluated in experiments performed in an olive-processing plant. All canned samples were sterilized at 121 degrees C for 30 min. Statistical analysis of the data indicated that the effects of darkening method and olive cultivar were the most pronounced. Acrylamide contents did not significantly differ after 6 months of storage. The small amounts of free amino acids and reducing sugars found in olives before sterilization did not significantly correlate with the acrylamide formed.
The effect of processing, with and without fermentation, upon the nutritional composition of pickled garlic was evaluated. On a dry basis, the fermented product had a higher content of riboflavin, alpha-tocopherol, and most individual amino acids but a lower thiamin level than the unfermented product. Ascorbic acid was totally lost during processing. The chemical scores for the unfermented and fermented product were 88 and 108%, respectively, with the limiting amino acid being leucine. Water blanching (90 degrees C for 4 min) affected only the ascorbic acid content, whereas fermentation significantly affected the contents of thiamin, ascorbic acid, and alpha-tocopherol, as well as glutamic acid and arginine. For each processing type, the effect of the preservation method and storage time on vitamins and amino acid composition was also analyzed. In the case of the fermented product, usage of the corresponding fermentation brine plus refrigerated storage was also assayed as the packing/preservation method and was found to give the best result from a nutritional standpoint.
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.
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