Microencapsulation technology is an alternative to stabilize stress factors and protect food ingredients or additives, which include environmentally sensitive bioactive principles in protective matrices to increase their functionality and life span. The objective of this research was to study conditions to obtain microcapsules with antioxidant capacity from a maqui (Aristotelia chilensis [Molina] Stuntz, Elaeocarpaceae) leaf extract by emulsification and subsequent retention after microencapsulation. Microcapsules were produced by water-in-oil emulsion (W/O) using a phase of the aqueous maqui leaf extract and gum arabic, and a liquid vaseline phase. Maqui leaf extract antioxidant capacity was 99.66% compared with the aqueous phase of the emulsion at 94.38 and 93.06% for 5% and 15% gum arabic, respectively. The mean yield of maqui leaf extract microencapsulation with 5% gum arabic varied between 38 and 48%, whereas with 15% gum arabic it was 39%. Once the antioxidant microcapsules were formed, mean extract antioxidant capacity ranged between 30 and 35%. Both yields responded similarly to changes in gum arabic concentrations (5% and 15%) in the aqueous phase of the emulsion; 5% concentration produced a microcapsule size from 1.0 to 10 μm. Maqui leaf extracts with high phenolic compound levels, which can be stabilized and protected by the microencapsulation process, produce new natural preservative systems as compared with their synthetic counterparts.

The detection of methicillin-resistant Staphylococcus aureus (MRSA) and other emerging strains in meat-producing animals and retail meat has increased the risk of contamination of food. The aim of this study was to determine the prevalence and characterize S. aureus strains isolated from the pork chain supply in Chile. A total of 487 samples were collected: 332 samples from pigs at farms and slaughterhouses (nasal, n = 155; skin, n = 177); 85 samples from carcasses at slaughterhouses; and 70 meat samples at supermarkets and retail stores. The isolation of S. aureus was carried out by selective enrichment and culture media. Biochemical testing (API Staph) and PCR (detection of the nuc and mecA genes) were used to confirm S. aureus and MRSA strains. The agglutination test was used to determine the protein PBP2'. Enterotoxins (SEA, SEB, SEC, SED) were determined by agglutination test and the se genes by PCR method. Oxacillin and cefoxitin susceptibility testing were carried out using the diffusion method. The overall prevalence of S. aureus in the pork meat supply was 33.9%. A higher prevalence was detected on carcasses (56.5%), in pigs sampled at farms (40.6%) than in pigs sampled at slaughterhouses (23.3%) and in nonpackaged retail meat (43.1%) than packaged retail meat (5.3%) (p ≤ 0.05). No significant differences (p > 0.05) were found between the prevalence in pigs (28.3%) and pork meat (32.9%) and between natural pig farming (33.3%) and conventional production (52.8%). The mecA gene and the protein PBP2' were not detected in S. aureus strains. Two S. aureus strains exhibited oxacillin and cefoxitin resistance, and one S. aureus strain was resistant to cefoxitin. One S. aureus strain isolated from a meat sample was positive for enterotoxin SEB. Although the mecA gene was not detected, oxacillin-resistant and seb-producing S. aureus strains were detected, which represent a risk in the pork chain supply.

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Water management efficiency is a key issue for sustainable agriculture development, since it is necessary to get a higher biomass production per unit of applied water. This study aimed to determine both water requirements and water use efficiency (WUE) and their effect on yield and quality parameters in carrots (Daucus carota L.), during the 2006 -2007 growing season in Chillán, Chile (36º 35' 43.2" S, 72º 04' 39" W, 140 m altitude). The water treatments applied were 25, 50, 75, 100 and 125 % pan evaporation (E pan ) in a Haploxerand soil under drip irrigation. The results showed that the highest crop yield was obtained with 100% E pan treatment. However, the highest WUE was found in the 75% E pan treatment equivalent to 3864 m 3 ha -1 , which is the recommended water application level in irrigation scheduling. Regarding carrot crop yield and quality parameters, statistical differences between the different water treatments were not significant, but the increase of applied water (125% E pan ) reduced plant density and root length. This relationship between yield and applied water will allow to improve the management of water resources under water scarcity.

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