Dietary supplementation with dried olive pomace in dairy cows modifies the composition of fatty acids and the aromatic profile in milk and related cheese

Abstract

This study aimed to evaluate the effect of dietary integration of dried olive pomace (DOP), a by-product of olive oil separation, on nutritional and aromatic properties of milk and cheese. Twenty dairy cows were divided into 2 groups that were balanced for milk yield, parity, and days in milk. The control group was fed a conventional diet (20 kg of dry matter/head per day), whereas the experimental group (EG) received the conventional diet supplemented with DOP as 10% of dry matter. During the trial, milk yield was recorded and the samples of milk, cheese, total mixed rations, and DOP were collected and analyzed to determine the chemical-nutritional composition and aromatic profile. Atherogenic and thrombogenic indices were calculated on the basis of the fatty acid (FA) profile of milk and cheese. Data were analyzed according to the mixed model for milk yield and chemical composition, including cows nested within treatment as a random effect, whereas the general linear model was used for the analysis of cheese parameters. Differences were assessed by Tukey's test. The EG diet had a lower content of palmitic, stearic, and linoleic acids and a higher level of oleic acid compared with the control. Dietary DOP integration did not affect milk yield and composition with the exception of protein content, which was greater in EG and significantly affected by diet and period. Instead, period was found to be significant for fat and casein in both groups. Dietary supplementation with DOP modified the FA profile of milk and cheese. There was a decrease in short- and medium-chain FA, but significance was achieved only for palmitic acid. The stearic, isomer trans of oleic (in particular vaccenic acid), oleic, and isomer trans of linoleic acids significantly increased. Monounsaturated FA increased in EG milk and cheese and saturated FA were significantly lower, whereas no difference was marked between the groups regarding level of polyunsaturated FA. Supplementation with DOP reduced atherogenic and thrombogenic indices and increased conjugated linoleic acid in both milk and cheese. The free fatty acids, ketones, lactones, esters, and phenylalanine catabolites were increased in raw milk, whereas only leucine metabolism was affected by diet in pasteurized milk cheese at both 1 and 30 d of ripening. The present results pointed out that DOP supplementation may improve the nutritional and nutraceutical properties and modify the aroma of milk and derived cheese.

Chemical–nutritional quality and oxidative stability of milk and dairy products obtained from Friesian cows fed with a dietary supplementation of dried grape pomace

“…These findings, summarized in Table , show the high content of phenolic compounds and the high antioxidant activity of this by‐product of the wine industry. The FA profile of DGP and diets administered to GP− and GP+ groups was also analysed (Table ) according to Castellani et al , evidencing a significant increase in the amount of linoleic acid in the experimental diet, as a consequence of DGP supplementation.…”

“…20 These findings, summarized in Table 2, show the high content of phenolic compounds and the high antioxidant activity of this by-product of the wine industry. The FA profile of DGP and diets administered to GP− and GP+ groups was also analysed ( Table 3) according to Castellani et al, 21 evidencing a significant increase in the amount of linoleic acid in the experimental diet, as a consequence of DGP supplementation. At the end of day 56 of the trial all cows were milked twice on the same day, once in the morning and once in the evening, and wileyonlinelibrary.com/jsfa the samples of each animal were mixed for individual analysis, and stored in the dark at 4.5 ∘ C before being analysed.…”

Zinc supplementation of Friesian cows: Effect on chemical-nutritional composition and aromatic profile of dairy products

“…Milk lipid fraction was extracted according to the AOAC official method (AOAC International, 2000), whereas in cheese, the extraction was performed as described by Domagała et al (2010) by using a mix of chloroform and methanol (2:1, vol/vol). Trans-methylation of lipid extracts and separation of FAME was performed following the procedure reported by Castellani et al (2017). Peak areas were quantified using Chro-meCard software (Thermo Fisher Scientific, Waltham, MA), and the relative value of each individual FA was expressed as a percentage of the total FA.…”

Phenolics and Antioxidant Capacity of Pitted Olive Pomace Affected by Three Drying Technologies

“…Second‐grade oil, known as olive pomace oil, can be removed from the pomace through solvent extraction and sold for household use (Yanık, ). Olive pomace is a suitable feed additive for cows, sheep, and water buffalo and has been shown to improve cows’ milk quality (Castellani et al., ). Olive pomace can also be used as a source of renewable energy as olive mill wastes have relatively high heating values, 20 to 23 kJ/kg on a dry basis (Miranda, Esteban, Rojas, Montero, & Ruiz, ).…”