What are genetically modified apples? It's GMO awareness month, which means the public cry against Genetically Modified Organisms (also called Genetically Engineered Organisms, abbreviated as GEOs) is in full tilt. It's therefore an appropriate time to let Canadians know that their beloved apples are also under threat of becoming unnaturally manipulated in the lab. In this 6 part blog series, I will detail the reasons for and against the proposed new breed of this delicious pomaceous fruit.
In Part 1, I had described the background for why a fruit growing company called Okanagan Specialty Fruits (OSF) based in Summerland, British Columbia, applied to Health Canada and the Canadian Food Inspection Agency for approval of a genetically modified apple (GM apple). In Part 2, I gave a brief background of what it means to genetically engineer an apple and I debunked the OSF's claim that GM apples safer than other GMOs. In Part 3, I discussed the potential ecological dangers and in Part 4, I described the potential biological (health-related) and economic consequences and dangers of the proposed GM apple. In Part 5 of this blog series, I consider whether or not developing and commercializing the GM apple is at all necessary, let alone favourable.
Questioning the Necessity of Genetically Modified Apples
Among the marketing claims made by OSF to promote GM apples is that preventing browning will help preserve the health-promoting polyphenols that make apples such a healing food. However, studies have showed that the total phenol content of an apple isn???t necessarily correlated with the susceptibility to, or extent of, browning. This suggests that browning may not appreciably degrade the nutritive value of an apple.
One study showed that in some varieties of apple (namely Classic/Red Delicious, Rhode Island Greening, McIntosh, and Cortland), the degree of PPO activity is a major factor determining the extent of apple browning whereas in other varieties (namely Empire, Rome, and Golden Delicious), the total phenolic concentration largely determines the extent of apple browning. This means that the extent of browning of an apple doesn’t necessarily indicate how much of the polyphenols have been degraded because different varieties (and also different individual apples harvested from a single tree) brown at different rates and for different reasons.
Another study including 10 cultivars (Shampion, Jonica, Gloster, Topaz, Ariwa, Rajka, Idared, Cortland, Alwa, and Braeburn) showed that 10 to 25 % of total polyphenols (mostly flav-3-ols such as catechin, epicatechin, and procyanidins) were lost in skin-on apple wedges after 5 days of cold storage (at 2 to 4 °C). Together, these data suggest that the browning process doesn’t appreciably decrease phenol content when consumers eat raw, fresh apples.
Moreover, several studies have indicated that apple phytonutrients are concentrated in the fruit peel, which is less susceptible or altogether resistant to browning compared to the fruit flesh. This further suggests that preventing apple browning is more important for cosmetic than for nutritional reasons.
Among the Okanagan growers opposing GM apples is Lee McFayden of Mariposa Organic Farm in Cawston. McFayden attests that several varieties of apple are naturally nonbrowning and that genetically engineering a new variety is unnecessary. In a recent phone interview, McFayden explained that Ambrosia, Honey Crisp, Fuji, and Braeburn varieties can be considered naturally nonbrowning and they all have similar flavour and texture characteristics that OSF claims the GM ArcticTM apple has.
McFayden clarified that given enough time, each of these apples will brown slightly, but the extent to which they brown is relatively minimal and the enzymatic browning process is very slow. One study conducted on Fuji apples confirmed that slices stored at 10 °C didn’t brown significantly and that treatment with ascorbic acid (vitamin C) further prevented browning of slices stored at the same temperature for up to 15 days.
While genetically engineering apples with silenced PPO genes will prevent browning, it doesn’t prevent tissue softening or microbial contamination, both of which are important factors affecting the safety, edibility, and shelf life of pre-cut and processed fruits that are stored for extended periods.
Extended storage of apples and other fruits has already been a problem in the past due to the use of chemicals such as 1-methylcyclopropene (abbreviated 1-MCP and marketed as SmartFreshTM by its manufacturer, Agro-Fresh) that slow fruit ripening. In 2005, The Sunday Times published an article explaining that the commercial use of 1-MCP allows distributors and processing companies to store apples for up to 1 year before selling them to consumers.
1-MCP is applied as a gas or spray to fruits in cold storage. It’s marketed as a taste- and nutrient-enhancing treatment, but it actually prevents softening of the fruit by inhibiting the synthesis and release of ethylene gas by naturally ripening fruit. Consumers typically aren’t made aware of when fruit has been harvested, and therefore don’t know whether or not the fruit they buy is fresh and nutrient-rich. A similar situation will almost undoubtedly arise if GM nonbrowning apples are approved for commercial use.
Apples in storage lose nutritional value over time, especially within the first month of storage, albeit certain storage conditions (such as chilling at temperatures of, or approximating, 0 °C) help to preserve the integrity of the fruit. However, any form of processing will compromise the nutritional value of an apple because it will stimulate the natural release of ethylene gas by the fruit. Ethylene gas contributes to ripening and tissue degradation of the processed fruit as well as fruits stored nearby.
Any apple that is processed prior to storage will be nutritionally inferior to the whole fresh fruit. The extent of nutrient loss will vary with the type of nutrient, apple cultivar, time of harvest, and other factors.
For example, an average apple contains 11 to 17 mg of vitamin C / 100 g of fruit. Slicing through the flesh leads to a loss of approximately 2.5 to 5 % of vitamin C (the amount of loss depends on whether or not the slice is treated with a preservative and on the thickness of the slice; thicker slices lose less vitamin C than thinner slices). Furthermore, storage for 5 days can lead to loss of antioxidant activity of 10 to 50 %, depending on the apple cultivar. Consumers will be purchasing nutritionally inferior fruits if nonbrowning GM apples are processed prior to being stored.
In Part 6, the concluding segment of this blog series on GM apples, I provide resources for learning more about GMOs and taking action, and I offer suggestions for how you can prevent apple browning naturally.
Look for the Non-GMO Project logo throughout the vitarock.com website to buy GMO-free certified foods and products such as those recommended below.
You can download a .pdf of the article in its entirety, including references, at the bottom of this page.