AAP, product safety and nutritional quality 215 11. 5 The effect of MAP on the nutritional quality of non respiring food products By using modified atmosphere packaging, the shelf-life of the packaged products can be extended by 50-200%, however, questions could arise regarding the nutritional consequences of MAP on the packaged food products. This section will discuss the effect of MAP on the nutritional quality of non-respiring food products while the effect of MAP on the nutritional value of respiring products, such as fresh fruits and vegetables, will be discussed in detail in the following sections Very little information is available about the influence of MAP on the nutritional quality of non-respiring food products. In most cases, for packaging non-respiring food products, oxygen is excluded from the atmosphere and therefore one should expect a retardation of oxidative degradation reactions Moreover, modified atmosphere packaged food products should be stored under refrigeration to allow CO2 to dissolve and perform its antimicrobial action. At these chilled conditions, chemical degradation reactions have only a limited No information is available regarding the nutritional consequences of enriched oxygen concentrations in modified atmospheres which can be applied for packaging fresh meat and marine fish. Some oxidative reactions can occur with nutritionally important compounds such as vitamins and polyunsaturated fatty acids. However, no quantitative information is available about these degradation reactions in products packaged in O2 enriched atmospheres 11.6 The effect of MAP on the nutritional quality of fresh fruits and vegetables: vitamin C and carotenoids During the last few years many studies have demonstrated that fruit and egetables are rich sources of micronutrients and dietary fibre. They also contain an immense variety of biologically active secondary metabolites that provide the plant with colour, flavour and sometimes antinutritional or toxic properties (Johnson et al., 1994). Among the most important classes of such substances are vitamin C, carotenoids, folates, flavonoids and more complex phenolics aponins, phytosterols, glycoalkaloids and the glucosinolates The nutrient content of fruit and vegetables can be influenced by various factors such as genetic and agronomic factors, maturity and harvesting methods, and postharvest handling procedures. There are some postharvest treatments which undoubtedly improve food quality by inhibiting the action of oxidative enzymes and slowing down deleterious processes. Storage of fresh fruits and vegetables within the optimum range of low O2 and/or elevated CO2 atmospheres for each commodity reduces their respiration and C2H4 production rates(Kader, 1986 Kader, 1997). Optimum CA retards loss of chlorophyll, biosynthesis of carotenoids and anthocyanins, and biosyntheses and oxidation of phenolic compounds11.5 The effect of MAP on the nutritional quality of non￾respiring food products By using modified atmosphere packaging, the shelf-life of the packaged products can be extended by 50–200%, however, questions could arise regarding the nutritional consequences of MAP on the packaged food products. This section will discuss the effect of MAP on the nutritional quality of non-respiring food products while the effect of MAP on the nutritional value of respiring products, such as fresh fruits and vegetables, will be discussed in detail in the following sections. Very little information is available about the influence of MAP on the nutritional quality of non-respiring food products. In most cases, for packaging non-respiring food products, oxygen is excluded from the atmosphere and therefore one should expect a retardation of oxidative degradation reactions. Moreover, modified atmosphere packaged food products should be stored under refrigeration to allow CO2 to dissolve and perform its antimicrobial action. At these chilled conditions, chemical degradation reactions have only a limited importance. No information is available regarding the nutritional consequences of enriched oxygen concentrations in modified atmospheres which can be applied for packaging fresh meat and marine fish. Some oxidative reactions can occur with nutritionally important compounds such as vitamins and polyunsaturated fatty acids. However, no quantitative information is available about these degradation reactions in products packaged in O2 enriched atmospheres. 11.6 The effect of MAP on the nutritional quality of fresh fruits and vegetables: vitamin C and carotenoids During the last few years many studies have demonstrated that fruit and vegetables are rich sources of micronutrients and dietary fibre. They also contain an immense variety of biologically active secondary metabolites that provide the plant with colour, flavour and sometimes antinutritional or toxic properties (Johnson et al., 1994). Among the most important classes of such substances are vitamin C, carotenoids, folates, flavonoids and more complex phenolics, saponins, phytosterols, glycoalkaloids and the glucosinolates. The nutrient content of fruit and vegetables can be influenced by various factors such as genetic and agronomic factors, maturity and harvesting methods, and postharvest handling procedures. There are some postharvest treatments which undoubtedly improve food quality by inhibiting the action of oxidative enzymes and slowing down deleterious processes. Storage of fresh fruits and vegetables within the optimum range of low O2 and/or elevated CO2 atmospheres for each commodity reduces their respiration and C2H4 production rates (Kader, 1986; Kader, 1997). Optimum CA retards loss of chlorophyll, biosynthesis of carotenoids and anthocyanins, and biosyntheses and oxidation of phenolic compounds. MAP, product safety and nutritional quality 215