Vol. 68, Nr. 3, 2003—JOURNAL OF FOOD SCIENCE 1051 Sensory and Nutritive Qualities of Food © 2003 Institute of Food Technologists Further reproduction prohibited without permission JFS: Sensory and Nutritive Qualities of Food Influence of Packaging Films on the Sensory and Microbiological Evolution of Minimally Processed Borage ( Borrago officinalis ) M. GIMÉNEZ, C. OLARTE, S. SANZ, C. LOMAS, J.F. ECHÁVARRI, AND F. AYALA ABSTRACT: The atmospheres prevalent in borage packaged in 5 different films, together with different water-vapor permeabilities of the films, determined the evolution of the visual and microbiological quality of borage. PVC films proved inadequate to extend the sensory quality since the samples packaged with the films were spoiled on day 9, whereas among the P-Plus films, the least permeable film was the most adequate to extend the sensory quality of borage until day 15. For most of the treatments, no correlation between the microbial growth and changes in appearance was found. Thus, some treatments with a fair sensory evaluation had microbial counts higher than those allowed by the European legislation. Keywords: borage, minimally processed vegetables, packaging films, sensory quality, microbial quality Introduction M INIMALLY PROCESSED FRESH (MPF) VEGE- tables or “grade 4” products are ready-to-eat vegetables and include fresh, washed, and chopped vegetables ready for use and packaged with sealed polymeric films or trays. This fourth form of trading (preceded by fresh, canned, and frozen) was developed in the 1980s as an answer to an emerging consumer demand for conve- nience and for high-quality and preserva- tive-free products with the appearance of fresh products, though less severely pro- cessed (Saracino and others 1991). The extension of the shelf life of MPF products is achieved by means of a combi- nation of correct refrigerated storage throughout the entire cold chain, a Modified Atmosphere Packaging (MAP), and good manufacturing and handling practices. MAP is a food-preservation technology whereby the composition of the atmo- sphere surrounding the product is different from the composition of air (O’Beirne 1990). In minimally processed vegetables, the gas composition in the package is modified by the respiration of the vegetative tissue (pas- sive modification). After a time, an equilib- rium-modified atmosphere (EMA) is creat- ed depending on the respiration activity of the product, the storage temperature, and the permeability characteristics of the pack- aging material. The permeability of the package depends on the characteristics and temperature of the packaging material, the thickness of the material, the type of perme- ating gas, and the differences in gas concen- tration across it (Exama and others 1993). Thus, passive atmosphere modification is a complex process with many interactions among different components. It is impor- tant to understand the interrelationships of the different parameters involved to design a suitable MAP system to preserve the qual- ity of a chosen commodity (Chau and Talasi- la 1994). Most of the MAP approaches to respiring products are based on a reduction in the O 2 and an increase in the CO 2 concentration. A low O 2 level and a high CO 2 concentration may delay the browning and spoilage of the fresh appearance; however, they also can cause off-flavors and flavor losses (Cam- eron and Smyth 1997). Many reports on the use of permeable polymeric films to extend the shelf life of minimally processed vegetables by means of the modification of the package atmospheric conditions (MAP) have been published (Priepke and others 1976; Kader and others 1989; Carlin and others 1990; Kwon and Lee 1995; Lee and others 1996; Mannapperuma and Singh 1998; Van de Velde and Hendrickx 2001). The main spoilage mechanisms af- fecting minimally processed vegetables are microbial growth, oxidation (enzymatic browning), and moisture losses. MAP is effec- tive at inhibiting these spoilage mechanisms, as well as at reducing the respiration rate of vegetables. However, MAP does not elimi- nate the need of good hygiene practices and refrigeration (Willocx and others 1994). Apart from the biochemical causes, food spoilage is caused by the growth of microor- ganisms that render the food unmarketable or inedible. It is characterized by undesir- able sensory changes in the color, texture, flavor, or odor. Microorganisms require certain defin- able conditions to grow and reproduce. In a food product, these conditions are either in- trinsic properties of the product, such as the pH and Aw , or extrinsic factors associated with the storage environment. Some of the most relevant extrinsic factors are the tem- perature and gaseous composition of the environment. These extrinsic factors can be controlled by means of MAP to delay the spoilage and extend the shelf life. Thus, a CO 2 concentration in excess of 5% (v/v) in- hibits the growth of most spoilage bacteria, especially psychrotrophic species. In gener- al terms, Gram-negative bacteria are more sensitive than Gram-positive ones. Never- theless, the survival of some pathogen mi- croorganisms such as Escherichia coli O157:H7, Listeria monocytogenes, or Aeromo- nas hydrophila in MPF products is a concern studied by many authors (Nguyen-the and Carlin 1994). Borage (Borrago officinalis L.) is a vegeta- ble that is very appreciated in the Ebro val- ley (in the north of Spain) with an annual production of about 15000 tons, but is less known in other regions. It is an annual herb half a meter high covered in a pubescent and even prickly epidermis that must be removed in the preparation stage. After peeling, the boiled fleshy stems are very pleasant to eat. The presentation of borage as a MPF product, ready to cook, would be very convenient for its commercialization to reduce the transport costs, the storage space and the preparation time.