Abstract
The use of agro-industrial by-products for ruminant feed represents both an economical and environmental convenient way for reducing waste discharge and waste management costs for food industries. Large amounts of waste from citrus processing industries are available in Sicily, Italy. In the present study, the effect of dried citrus pulp as sheep dietary supplementation was evaluated on physico-chemical, microbiological and fatty acid composition of resulting milk and cheese. Pelleted feed integrated with molasses and blond orange pulp, replacing cane molasses, beet pulp and part of the maize and sunflower in ration, were administrated to ewes as an experimental treatment The experiment involved sixty Comisana breed sheep divided into two groups and two feeding trials (experimental and control). Ewe's milk and cheese samples were collected from January to April and analyzed for physico-chemical, microbiological and fatty acid profile composition. Results suggested that both the experimental milk and cheese were different from the controls. In particular, an increase of experimental milk yield and fat content were registered whilst the cheese samples exhibited a significant decrease of pH values and an increase in fat and protein contents. In addition, an increase of conjugated linoleic acids as well as of the oxidative stability were observed indicating the beneficial effect of dietary supplementation. Furthermore, among the main microbial groups, the experimental and control samples, no differences were detected. However, with the exception of streptococci, which was found higher in experimental cheeses, and staphylococci, which was significantly reduced by experimental feed. Moreover, the application of culture-independent methods highlighted the dominance of Lactobacillus rhamnosus/casei group in the experimental cheese, suggesting a driving role of the dietary supplementation in the cheese microbiota composition. The present study demonstrated that the inclusion of citrus by-products in the diet of small dairy ruminants is a promising feeding, which could positively affect milk composition and cheese manufacture.
Highlights
The use of agro-industrial by-products for ruminant feed is both an economical and environmental way to reduce waste discharge and decrease waste management cost [1]
The aim of this study was to investigate the effect of replacement of cane molasses and beet pulp, used in conventional fed, with molasses and dried orange pulp on physico-chemical, microbiological and fatty acid composition of Comisana sheep’s milk and cheese manufacturing
During the experimental period a commercial pelleted feed was administered to the control group (C) while a pelleted feed integrated with 4% (DM basis) of molasses and 10% (DM basis) of blond orange pulp were offered daily to ewes of the experimental group (E) in replacing the cane molasses and beet pulp present in the pelleted feed of the control group (Table 1)
Summary
The use of agro-industrial by-products for ruminant feed is both an economical and environmental way to reduce waste discharge and decrease waste management cost [1]. The residues of the juice extraction comprise of peel, pulp, rag and seeds These components, either individually or in various combinations, are source materials from which by-product feedstuffs can be obtained [3, 4]. The inclusion of citrus by-products in the diet of small dairy ruminants had some effects on milk yield, composition and properties and on the quality of derived products [8]. Some researches have investigated the effects of different feeding systems on the quality and composition of milk and dairy products, up to now, no information is available on the influence of agro-industrial by-products, such as orange pulp, as sheep dietary supplementation on Sicilian ewe’s milk and cheese
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