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Three Mayan Indian towns in the highlands of Guatemala were selected for a field research project by the Institute of Nutrition of Central America and Panama (INCAP). As part of the exploratory phase of the project a dietary survey was made in each of the three towns, and was repeated every year for 4 years in order to compile detailed information on the food consumption of preschool children. The collection of such information, on an individual basis, presents many problems, particularly when dealing with children in this age group, and it was often necessary to study the total family consumption simultaneously. The survey included, therefore, both preschool children and their families, and was designed, not only to estimate the nutrient intake on one particular occasion, but to learn also if such intakes varied from time to time or remained at about the same level.The opportunity seldom occurs of studying the food habits of communities over 4 years and at the same time to observe the people's reaction to different methods of inquiry. Flores and her colleagues conducted surveys on previous occasions in two of the towns (Flores & Reh, 1955; Flores, Flores & Meneses, 1957). Representative population samples were taken in which the family consumption was recorded over a period of 7 days. The results of these earlier surveys were similar to the figures obtained during the study now recorded. E X P E R I M E N T A LThe communities studied. One of the main characteristics of these rural villages is the social and economic homogeneity of the families. Most of these Indian families are very poor. They live in huts, wear typical Indian dress and speak their native languages. The majority of the schoolchildren and the men also speak Spanish, the former in school and the latter with Ladino persons in the markets where they sell their goods.All the men are farmers and work their own land, maize and beans being the staple crops. Occasionally, when space permits, they grow fruits and vegetables near their homes. Some of the women weave cloth for domestic use as well as commercial items which they carry to the city markets. 18

The use of EOs nanoemulsion to develop active edible films offers a new way to modify transport properties and to release active compounds while improving mechanical resistance, transparency, and antioxidant and antimicrobial activity. The aim of this study was to study the influence of homogenization conditions and carvacrol content on the microstructure and physical properties of edible nanoemulsified chitosan films. Film-forming emulsions (FFE) were prepared with chitosan (1.5%), Tween 80 (0.5%), and carvacrol (0.25%, 0.5%, and 1.0%); two homogenization methods were used (rotor-stator and rotor-stator followed by high-pressure homogenization). Film internal and surface microstructure was characterized by scanning electron microscopy (SEM) and film physical properties, such as mechanical, optical, and water barrier, were evaluated. Results showed that the high-pressure homogenization method promoted a significant change on film microstructure, leading to improved properties. Carvacrol droplets were smaller and homogeneously distributed in the film when 0.5% (v/v) carvacrol was incorporated (1:1 Tween 80: carvacrol ratio). As a consequence, emulsified films obtained at high pressure were less opaque, had greater elongation, and had a lower permeability to water vapor than those obtained by the rotor-stator method. Therefore, high-pressure homogenization is a good method to obtain edible emulsified films with desirable properties for food preservation.

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