The biggest problem consumers experience with fresh produce and apples especially, is browning due to oxidation. There are several measures you can take to keep your fresh apples from being wasted. You can store them in optimal conditions, treat them prior to storage, and get your apples from the most natural growers you can find.
First, a little about oxidation: the process takes place when the polyphenol oxidase (PPO) enzymes are exposed to oxygen in the air, after the apple flesh is cut. PPO enzymes are responsible for apple color, taste, and texture, which means that different varieties will be more or less susceptible to browning. The apples are naturally slow to brown, are varieties with thicker skin such as Fuji, Rome, and Granny Smith, which are also harvested later in the season. Some earlier season varieties with thinner skins are Gala, Red Delicious, and Golden Delicious which brown slightly faster. One early season variety, the Ginger Gold, is extremely resistant to browning and the sweet-tart flavor makes them great for many uses. As the name would suggest, natural antioxidants slow down the oxidation process. The same can be said about acidic compounds, as oxidation takes place in more alkaline environments.
A controlled location for apple storage is one of the most important aspects to consider. The ideal temperature for apple storage is 32º – 46º F with 90 to 95 percent relative humidity. The refrigerator is the only recommended option, and the crisper drawer is the ideal place in the refrigerator. Ideal storage conditions reduce apple oxidation, and pre-storage steps can prevent apples from browning even further.
To prepare your apples for storage it depends on whether you want them left whole, or whether you are cutting them prior to storing.
To store apples with the peel intact the most important thing is to reduce the contact with other produce. So in the refrigerator, it is important to give apples their own drawer and keep gases from building up and affecting the oxidation process. For larger storage solutions it can be helpful to store same apple varieties together in storage bins in a refrigerator, which also helps with organization.
Obviously, canning produce was invented to prevent the oxidation process and to allow produce to be stored for longer. Canning cuts out oxygen exposure completely and adds antioxidant preservatives, so that is the best solution for long term storage. Not every situation calls for canning, and it can be a hassle, but there are elements in canning that can be used for shorter storage. These methods will require apples to be either cut or peeled whole to expose the fruit flesh As mentioned earlier acidic compounds balance the pH levels of the apples, so coating apples in lemon or pineapple juice prevent browning. There is even a concentrated citric acid powder for preserving fruits called Fruit Fresh! Sugar can also stop the diffusion of oxygen, so if you are going to sweeten your apples, why not do it ahead of time to preserve them?
The final thing you can do to minimize the browning of your apples is to get apples from high-quality orchards. We have talked about the different effects of fertilizers and pesticides, while sometimes necessary they affect the fruit the more they are used. Since fertilizers change the pH of the soil that same imbalance is present in the fruit. In the Shenandoah Valley, our natural limestone soil greatly reduces the need for fertilizers to grow big delicious apples, so our apples brown much slower than the apples grown in fertilizer heavy soils. If you want to know more about how soil affects fruits read our previous post here: https://www.turkeyknobgrowers.com/blog/detail/the-tastiest-apples
Some apples oxidize at a slower rate. Here is some information on a couple of these varieties.
This is an early-season apple that browns much slower after being cut. Ginger Gold is a delicious sweet-tart apple. It is one of the earliest varieties to ripen, bearing fruit in August (in some areas even earlier). This apple was first discovered right here in Virginia in the late 1960s, this sweet-tart apple variety is ideal for salads, but it also makes a great baked apple and a delicious, fine and very white apple sauce.
We, at Turkey Knob, do not have any of these planted – this is just for your information.
The Arctic Apple is a genetically engineered apple developed by Canada-based Okanagan Specialty Fruits. It is particularly desirable due to its non-browning flesh. While there are plenty of non-GMO apple varieties that are slower to turn brown, the Arctic Apple is the only one so far to resist oxidation process. It is Ideal for salads and other recipes that call for sliced or diced apples.
We hope these tips will help you keep your apples longer and prevent browning from oxidation. If you have problems with apples going bad faster it might be time to try out a local orchard for better-tasting and longer-lasting apples. Fresh apples are always the best so keep your stock as fresh as possible.