Physical, Nutritional, and Sensory Properties of Cheese Obtained from Goats Fed a Dietary Supplementation with Olive Leaves

Abstract

The aim of this study is to evaluate the physical, nutritional, and sensory properties of cheese obtained from goats fed a dietary supplementation with olive leaves (OL). Thirty Saanen goats were randomly allocated into two groups of 15 goats each, (1) a control group fed with a standard diet (CG), and (2) an experimental group (EG) fed an OL-enriched diet. The trial lasted for 30 days. The milk of each group was then collected and used to produce Caciotta cheese, which was analyzed at the beginning and at the end of the ripening period (60 days). The results showed a positive effect of dietary OL supplementation in improving the fatty acid profiles due to the significant increase of unsaturated fatty acids, mostly α-linolenic acid (C18:3 n-3), with the consequent reduction of the ω-6/ω-3 ratio, a condition commonly associated with an increased health functionality of food products. Moreover, improved oxidative stability was observed in cheese during ripening, a presumable consequence of the transfer into the milk of dietary bioactive compounds, mainly polyphenols of high biological value, and credited as a marked antioxidant potential. Furthermore, reduced lipolytic action was observed in 60-day ripened cheese, even if no significant changes in sensory properties were evidenced.

Whole Blood Transcriptome Profiling Reveals Positive Effects of Olive Leaves-Supplemented Diet on Cholesterol in Goats

“…In the last decade, experimentations concerning the use of agri-food by-products as dietary ingredients for farm animals had a significant boost mainly due to the need to valorize these plant matrices, the disposal of which represents both an environmental and economic issue. In the specific case of OL as a feeding ingredient for dairy ruminants, several studies have been conducted, which, even recently, have characterized the aspect concerning the potential effects on the quality of milk but also fresh and ripened cheeses [ 13 , 14 , 15 ]. To our knowledge, there is, however, a lack of information regarding the effect of this feeding strategy on animal metabolism, an aspect that can contribute to obtain clarifications about variations observed in the nutritional qualities of obtained dairy products, as well as on the animals’ health.…”

“…In particular, dietary supplementation was performed by including extruded linseed in the ration. As is known, linseed is rich in polyunsaturated fatty acids, with relevant concentrations of linolenic acid (C18:3 cis-9, cis-12, cis-15), which also represent the major fatty acid detectable in the OL used in this trial [ 15 ]. Contrary to what has just been reported, no changes in milk cholesterol were observed in the study conducted by Symeou et al [ 35 ], in which lactating Chios ewes were fed diets supplemented with ensiled olive cake.…”

“…This study is part of a wider experimentation concerning the effect of an OL-supplemented diet on lactating goats, with the purpose of focusing the attention on both the qualitative characteristics of milk and cheese and the biochemical and molecular aspects influenced by the diet. For this reason, the experimental design has already been described [ 15 ]. Briefly, the trial lasted 30 days and involved 30 Saanen goats homogeneous for age (46 ± 2 months), weight (52.7 ± 4.3 kg), lactation days (86 ± 7 days in milk), milk yield (2296 ± 281 g/day), and a body condition score (BCS) equal to 2.78 ± 0.18.…”

“…At the beginning of the experimentation, the animals were evenly separated into two groups that were indoor housed in two adjacent but separate areas characterized by a space shared by goats belonging to the same group, a drinking trough, and provisional single bunks on straw, useful for the individual administration of the diets. Each goat received polyphite daily hay ad libitum, while twice daily (in the morning and in the evening) was administered a custom-formulated concentrate (a total of 1 kg/head) whose ingredients and chemical composition have been previously reported [ 15 ]. The control group (CTR) was fed a standard diet that was formulated by taking into account the nutritional needs of lactating goats, while the experimental group (OL+) received the same basic diet but supplemented with 10% OL on a dry matter (DM) basis.…”

“…A significant improvement in the milk fatty acid profile was however evidenced in lactating animals compared with animals fed conventional diets. More recently, the efficacy of an OL-supplemented diet in inducing an increase in concentration of linolenic acid in goat milk was confirmed; furthermore, an improvement in the oxidative stability of derived dairy products was observed, probably as a consequence of the reduction of lipolytic events during storage and ripening [ 13 , 14 , 15 ].…”