A Descriptive Study of Vitamin and Mineral Losses in Canned Vegetables

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De La Salle University – Manila

Br. Andrew Gonzalez College of Education

Department of English and Applied Linguistics

A Descriptive Study of Vitamin and Mineral Losses in

Canned Vegetables

In partial fulfillment for the requirements of Basic Research Skills/

English for Specific Purpose

Submitted by:

Cary Chan

Sean Tiu

Submitted to:

Miss Cynthia Correo

Date:

April 11, 2016

Acknowledgments

        The researchers would first like to thank God for guiding the researchers throughout this research paper. Without His wisdom and guidance, this research paper would not have been completed. All glory and honor unto Him.

        Secondly, the researchers would like to thank our ENGLRES professor Miss Cynthia Correo, for constantly guiding us throughout this research paper, and always being available for consultation. Her invaluable comments have greatly helped improve this paper.

        The researchers would also like to thank those who willingly gave time to be interviewed. Their responses have helped support the findings of the study.

1.0 Introduction

There has been constant discussion on whether fresh foods or canned foods contain more nutrients (vitamins and minerals). Newspaper publisher, Inquirer, published on their website an article sponsored by processed food company “Jolly” claiming that nutritional loss in canned vegetables  (with emphasis on corn and mushrooms) are virtually non-existent (Roberto, 2015). The article elaborates that the reason for this is because the canned vegetables were directly harvested from a fresh source. The article claims that canned vegetables can be used to substitute fresh vegetables in home cooking and daily consumption. However, studies have consistently shown that there is indeed more nutrient loss in canned foods, even when the vegetables used in canning are taken directly from a farm. Fresh food have been proven to contain more nutrients if they are directly consumed after harvest or if they are bought from a local farmers’ market (Springer, 2012). However, Springer states that nutrient loss may occur in fresh foods especially during long processes of shipping or when fresh vegetables are harvested before peak ripeness. Numerous studies have affirmed that nutrients contained within fresh vegetables degrade during the process of canning because of their sensitivity to heat, light, acidity, among others.

A study by Lešková, Kubíková, Kováčiková, Košická, Porubská, & Holčíková, (2006) showed the different amount of percentages of vitamin degradation as different meats and vegetables are subjected to different types of heat treatment.  They used mathematical models to represent these losses. A similar study by Rickman, Barrett. & Bruhn (2007) also compared the amount of nutrients when food is fresh, canned, or frozen.

With these conflicting findings, this study aimed to show the general trend of nutrient loss (with few exceptions) for each vitamin and mineral specifically in vegetables when exposed to the individual processes of canning –e.g. blanching and heating and to use the empirical data gathered to arrive at a conclusion that canned vegetables are less nutrient-rich than fresh vegetables.  Previous studies and experiment results have been confined to showing the percent weight loss of the vitamin and mineral for only one or two types of food items. This study therefore, aimed to fill that gap by studying previous experiment results, as well as the nature of the nutrients found in the aforementioned food items, using the outputs and findings of previous research as supports for this study. The research was limited to canned goods, specifically vegetables and fruits and fungi regarded and used as vegetables in cooking (e.g. mushroom, tomatoes, and beans). In addition, the research only tackles the current way of canning and preservation.

2.0 Review of Related Literature

        The history of canning traces back its roots in the 18th century, when French troops faced the dilemma of a food shortage especially since they fought battles in Italy, Germany, and even in the Caribbean. Out of necessity, finding an efficient method of preserving food capable of withstanding differing weather conditions and temperature changes was needed. In 1803, a young chef named Nicolas Appert found success in bottling peas. He found that making the container airtight and subjecting the peas to heat made a good way of preserving food. Not long after, he also experimented on a plethora of food items including vegetables, fruits, meats, dairy products, and fish. The glass bottles eventually evolved into tin-plated steel or cast iron in 1804. In 1904, Max Ams Machine Company founded and patented the double-seam processed used in most food cans today, paving the way for the modern method of canning and preserving food (Barksdale, 2014).

2.1 The Canning Process

2.1.1 Trimming and washing

        According to Murano (2003), the first step of canning involves harvesting the vegetables. The harvested vegetables are then trimmed of any inedible plant matter, including roots, pods (in the case of peas), pits, and other parts of the vegetables. The trimmed vegetables are then, soaked in water and disinfectants such as chlorine or other detergents and agitated in order to remove unwanted dust or debris. Alternatively, the vegetables are sprayed with pressurized water to remove unwanted debris on the vegetable. The vegetables are also sometimes cut; after this process the vegetables are then sent to the next step—blanching.

2.1.2 Blanching

        Blanching is a unit operation before the processes of freezing, canning, or drying in which fruits and vegetables are heated in order to inactivate enzymes; modify texture; preserve color, flavor, and nutritional value; and remove trapped air. The most commonly used heating media for blanching in industry are hot water and steam, but microwave and hot gas blanching have also been studied. Different hot water and steam blanchers have been created to improve the quality of products, increase the amount of yield, and facilitate the processing of products with different thermal properties and geometries. More recently, the conservation of energy and reduction of waste have become a reason to further improve the equipment design. Although blanching seems a simple operation, transfer of heat to a certain bed of product and its effect on the product are very difficult to accurately model with predictive mathematics. Processing conditions are usually set up to inactivate enzymes, but other quality specifications, such as color and texture, are commonly monitored. For a given product, usually the mass flow rate is constant, temperature is measured, and heating media flow rate is adjusted to assure that the temperature is kept at the set point. Because most vitamins are sensitive to heat, significant amounts of vitamins are degraded in this process (De Corcuera, Cavalieri, & Powers, n.d.). Data from the researchers’ interview suggests that cut vegetables are more prone to vitamin degradation, with larger areas exposed to steam or water.