Sunday, 12 February 2012

Substituting Synthetic Colorants, Nitrates and Nitrites in Sausages with Natural Plant Extract Colorants

Background/ Introduction

Color is an imperative aspect influencing consumers’ acceptability of food products (Feiner, 2006; Kerry 2002; Cornforth, 1994). This is because consumers always correlate food color with food quality i.e. freshness, juiciness, and food safety (Adamsen 2006). Thus, according to Muntean (2005), the use of colorants as additives for food and drinks is a significant factor to food manufacturers and influences consumer perception of processed foods. For manufacturers, added colorants assist in ensuring batch-to-batch uniformity and help reinforce colorants that are already present but are less intensive than the consumer would expect. For the consumer, added colorant help to restore the original appearance of foods whose natural colorant content as been reduced by processing treatments. Colorants also provide appealing and readily identifiable products. As a result, it is a common practice in industry to improve, or even to change the color of foods, adding natural or synthetic colorants (Muntean, 2005)

Color formation and color stability are important sensory attributes of meat products which influence the products’ acceptability by consumers (Zhang et al., 2007; Becker, 2002; Cornforth, 1994; Myoglobin (80%) and hemoglobin (20%) are the predominant meat pigments and they account for the red color in fresh meat ( However, the intensity of hemoglobin found in the arteries, veins and capillaries is lost after slaughter. Also during cooking/processing, browning occurs and this is undesirable (Nicola and Rosemary, 2006). Artificial colorants, nitrites and nitrates impact color in meat products. The pigment responsible for the characteristic pink color of cured meat is a ferrous complex of myoglobin containing nitric oxide (NO), namely, nitrosylmyoglobin (or NO-Mb). The complex is formed by the reaction of myoglobin with NO generated from nitrite (Zhang et al., 2007; Stevananoic and Sentjurc, 2000). Nitrosohemachrome is a denatured, stable form of NO-Mb in cooked, cured meats (Zhang et al., 2007). Delgado and Lopez (2003), Zdzislaw, (2002), and Østerlie and Lerfall (2004) all reported that consumer preference for naturally derived colorants is associated with their image of being healthy and of good quality. Nitrates, nitrites, and synthetic colorants tend to be perceived as detrimental to health (Zhang et al., 2007; Stevananoic and Sentjurc, 2000). Østerlie and Lerfall (2004) reported that synthetic colorants are being measured accountable for many allergenic and intolerance reactions amongst consumers of such products.

Problem Statement  

Potassium and sodium salts of nitrites and nitrates are among the most widely used of all food additives (Stevananoic and Sentjurc, 2000). Their role in meat curing include; to develop and fix the color (pink), to inhibit microorganisms (Clostridium botulinum), acts as an antioxidant and develop characteristic flavors (Fennema, 1996; Feiner, 2006; Stevanovic and Sentjurc, 2000; Cornforth, 1998). Some processors have used synthetic food colorants to impart the desired pink color in cured meats (Østerlie and Lerfall, 2004).                                                                                                            Despite the above desired properties, the safety of synthetic colorants, nitrites and nitrates to human health has been questioned during the last 20 years (Stevananoic and Sentjurc, 2000; Zhang et al., 2007). Stevananoic and Sentjurc (2000); Fennema(1996); and Feiner(2006), all agree that nitrites are involved in formation of low but possibly toxic, levels of nitrosamines in certain cured meats. Nitrates and nitrites react with amines, amides and amino acids in meat and meat products forming carcinogenic N-nitroso compounds known as N-nitrosamines such as N-nitrosopyrolidin and N-nitrosodimethylamine (Stevananoic and Sentjurc, 2000). Moreover, the residual nitrites present in cured meat may also lead to the formation of carcinogenic N-nitroso compounds in the gastrointestinal tract (Zhang et al., 2007). Numerous studies have confirmed nitrites’ contribution to a variety of cancers including colorectal, stomach, and pancreatic cancers (Ferguson, 2010).

Thus the demand for natural and organic processed meat and meat products (sausages) that are healthy and cancer free is a momentous part of the explosive market growth that is occurring in meat and meat products industry (Sebranek and Bacus, 2007). Østerlie and Lerfall, (2004); and Sebranek and Bacus (2007), further confirmed this when they reported that consumers perceive artificial colorants, nitrites and nitrates added to meat and meat products as unhealthy and low quality.

There is need to find alternative sources of color that are natural, organic, non carcinogenic (healthy), and reliable which can competently substitute artificial colorants, nitrates and nitrites with minimal or no quality compromise in terms of color and/or appearance.

Major Objective

The study aimed at substituting synthetic food colorants, nitrites and nitrates used in sausages with reliable natural plant extract colorants.

Specific Objectives

The objectives of the study were to;

  • Identify plants/or plant parts whose extracts can be used as potential food (sausage) colorant.( red amaranthus, tomatoes, water melons and Hibiscus spp (Acer plant, locally known as ‘musayi’)
  • Determine the color intensity of the obtained fruit juices and plant extracts.
  • Study the affect of different temperatures on the stability of the identified colorant(s).
  • Determine the internal color of sausages (kept under refrigeration, before cooking and after cooking) as measured using a Color Difference Meter (Tintometer model E).
  • Determine the acceptability of sausages colored with plant extract colorant.
Research Hypothesis.

Natural plant extracts colorants can be impart an acceptable stable pink color to sausages.


Identifying a potential natural plant extract colorant that can proficiently substitute the artificial colorants, nitrates and nitrites with minimal difference in the color of sausages will either reduce or perhaps eliminate the use of artificial colorant, nitrites and nitrates. This will possibly reduce the risk of cancer associated with the use of artificial colorants, nitrites and nitrates in sausages. This is further justified by the consumers’ willingness to pay significant premiums for organic and natural foods. Sebranek and Bacus (2007) reported that premiums of 10-40% for organic foods over conventional products were common. For meat and poultry, premiums of 200% or even more have been reported.

Note that all references used in all postings related to the topic of sausages, meat and meat product colorings will be posted in the last article about this topic.
About the author
Mr. Sempiri Geoffery, the author of this article
graduated from Makerere University with a Bsc In Food Science and Technology Degree in January, 2011.