Use of spray cooling technology for development of micro-encapsulated capsicum oleoresin for the growing pig as an alternative to in-feed antibiotics : Study of release using in vitro models

¹ Equipe de Recherche Technologique 'Conception, Ingénierie et Développement de l'Aliment et du Médicament', Centre de Recherche en Nutrition Humaine, Faculté de Pharmacie, Université d'Auvergne, 28 place H. Dunant, 63001 Clermont-Ferrand, France
² Animal Nutrition, Management and Welfare Research Group, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
³ ERBO Spraytec A.G., 4922 Buetzberg, Switzerland

^* To whom correspondence should be addressed. E-mail: j-philippe.meunier{at}u-clermont1.fr.

	Abstract

The aim of this study was to develop sustained release microspheres of capsicum oleoresin as an alternative to in-feed additives. Two spray cooling technologies, a fluidized air bed using a spray nozzle system and a vibrating nozzle system placed on the top of a cooling tower, were used to microencapsulate 20% of capsicum oleoresin in a hydrogenated rapeseed oil matrix. Microencapsulation was to reduce the irritating effect of capsicum oleoresin and to control its release kinetics on consumption by the animal. Particles produced by the fluidized air bed process (batch F1) ranged from 180 to 1,000 µm in size. The impact of particle size on release of capsaicin, the main active compound of capsicum oleoresin, was studied after sieving F1 to obtain 4 formulations: F1a (180 to 250 µm), F1b (250 to 500 µm), F1c (500 to 710 µm), and F1d (710 to 1,000 µm). The vibrating nozzle system can produce a mono-dispersive particle size distribution. In this study, particles of 500 to 710 µm were made (batch F2). The release kinetic of the different formulations was estimated in a flow through cell dissolution apparatus (CFC). The time to achieve 90% dissolution value of capsaicin for sub-batches F1 increased with the increase in particle size (P < 0.05) with a highest value of 165.5 ± 13.2 min for F1d. The kinetics of dissolution of F2 was slower than all F1 sub-batches with a T90% value of 422.7 ± 30.0 min. Nevertheless, as CFC systems are ill suited for experiments with solid feed and thus limit their predictive values, follow-up studies were performed on F1c and F2 using an in vitro dynamic model (TIM) that simulated more closely the digestive environment. For both formulations a lower quantity of capsaicin dialyzed was recorded under fed condition vs. fasting condition with 46.9% ± 1.0 vs. 74.7% ± 2.7 for F1c and 32.4% ± 1.4 vs. 44.2 % ± 2.6 for F2, respectively. This suggests a possible interaction between capsaicin and the feed matrix. Moreover, 40.4 ± 3.9% of the total capsaicin intake in F2 form was dialyzed after 8 h digestion when feed had been granulated vs. 32.4 ± 1.4% when feed had not, which suggests that the feed granulation process could lead to a partial degradation of the microspheres and to a limitation of the sustained release effect. This study demonstrates the potential and the limitations of spray cooling technology to encapsulate feed additives.

Key Words: capsaicin, capsicum oleoresin, microencapsulation, spray cooling

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