Typology and quality preference of plant leaves used for food packaging in Benin
Plant leaves are used to package various local foods in Benin. Vegetable packaging is a good alternative to plastic packaging in use in the country. A better knowledge of these plants and their different uses is necessary for their valorization. This study aims to identify the plant resources that are used in Benin as food packaging and to determine their preferable characteristics according to food processors and consumers. A survey was carried out considering 300 food processors and 300 consumers in ten municipalities in Benin. The leaves of 58 plant species belonging to 30 families have been identified and are used to pack 29 different types of food sold in the different markets of the survey areas. The choice of a leaf by processors and consumers is performed according to well-defined criteria. The main criteria used by processors are tear resistance (86%), food shelf life (82%) and size (69%), while consumers use organoleptic characteristics (78%) and food shelf life (51%) of the leaf. For all foods, about six major species of leaf including Musa sapientum, Tectona grandis, Thalia geniculata, Manihot esculenta, Gmelina arborea and Isoberlinia doka have the best characteristics according to processors and consumers. Before the leaves are used as food packaging, processors usually apply treatments that are supposed to improve the tear resistance of the leaves and reduce microbial contamination. Regarding the characteristics of these leaves at food artisanal scale, they are potentially good base material useful to produce leaf plates or modern food biodegradable packaging.
Food packaging is used to facilitate the protection, transport and storage of food (Robertson, 2006; Wikström et al., 2014; Ribeiro-Santos et al., 2017). Depending on the manufacturing materials, several types of packaging are available on the market with different characteristics: plastic (the largest in volume produced), paper and cardboard (primary material in value), glass, wood, metals and composites (mixture of several materials) (Marsh and Bugusu, 2007). Likewise, researchers and manufacturers have developed modern packaging (active, intelligent, functional and bioactive packaging) capable of actively interacting with food and their environments or providing information on the state of the freshness of food (Realini and Marcos, 2014; Meena et al., 2017). Among all these types of packaging, those made from plastic materials dominated in food industry because of their practical and aesthetic character (Siracusa et al., 2008; Malathi et al., 2014). This petro-based food packaging is nonbiodegradable and has replaced a part of the natural packaging that has been used in the world for many centuries (Mustafa et al., 2012; Ribeiro-Santos et al., 2017). This non-biodegradable packaging is used massively and invades as well as urban and rural areas. But because of their non-biodegradable nature, they present several issues including environmental pollution, unhealthy cities and the stuffing of gutters (Adejumo and Ola, 2008; Onzo et al., 2013; Shaikh et al., 2021).
This situation in developing countries has led several countries to put in place regulatory policy which aims to forbid the use of non-biodegradable plastic packaging. The Republic of Benin voted in December 2017 the law No. 2017-39 prohibiting the production, export, marketing, possession, distribution and use of non-biodegradable plastic bags in the country.
Similarly, environmental and public health challenges have increased and have stimulated innovations in food packaging. In this context, natural and biodegradable synthetic packaging constitutes an exploitable resource for finding an alternative solution to non-biodegradable packaging (Davis and Song, 2006). Indeed, before the emergence of nonbiodegradable packaging, food production technologies used plant and animal materials to package food (Gupta and Dudeja, 2017). Today, although non-biodegradable packaging is widespread all over the world, plant packaging continues to be used in many regions of the world, mainly in Africa, Asia and South America (Adegunloye et al., 2006; Ahmadi et al., 2019; Kora, 2019). Some plant species used to wrap food have been identified and characterized in Nigeria (Adegunloye et al., 2006), in Ghana (Mensah et al., 2012) and Benin (Onzo et al., 2013, 2016).
According to Onzo et al. (2013), besides the protective function that these packages provide, they transfer aroma or colour to packaged foods, while others are also eaten as leafy vegetables or used for their medicinal properties (Mostafa, 2021). Mensah et al. (2012), Onzo et al. (2014) and Zannou et al. (2016) reported that leaf packaging contains physicochemical compounds such as proteins, lipids, minerals, vitamin C and phytochemicals such as tannins, anthocyanins, flavonoids, alkaloids, etc. that could migrate from the leaves to the food. Also, the leaves of some species such as Daniella oliveri and Thalia geniculata used as food packaging have antimicrobial properties and preserve food quality during storage (Onzo et al., 2015).
In part of the valorization of plant packaging in Benin, some studies have been carried out to provide information on the types of plant packaging, uses, treatments and physical properties of the leaves of plants used as food packaging. However, the most suitable leaf packaging for each food and the criteria for assessing the quality of leaf packaging are not well documented.
The objectives of this study were therefore (i) to inventory the plant resources used as food packaging in Benin (ii) to determine the criteria for assessing the quality of plant packaging and (iii) to identify the best leaf packaging used for food production in Benin.
Source : Typology and quality preference of plant leaves used for food packaging in Benin
