How long should walnut kernels be frozen for storage

Walnut kernels can generally be stored for 6-12 months in frozen storage, depending on factors such as packaging sealing, temperature stability, and the initial state of the walnut kernels.

1. Sealing Effect

Using vacuum packaging or double-layer sealed bags can significantly extend the shelf life. Air contact can cause oxidation and spoilage, and unsealed walnut kernels are prone to develop a crackling taste when frozen. It is recommended to divide into small portions and release the air from the bag before sealing to avoid repeated thawing.

2. Temperature stability

Maintaining a constant temperature below -18 ℃ is key. Frequent opening and closing of household refrigerators can cause temperature fluctuations and accelerate fat oxidation. The independent freezer has better storage effect, and temperature fluctuations controlled within 3 ℃ can maintain flavor.

3. Initial state difference

Fresh shelled walnut kernels are more resistant to storage than aged ones. The walnut kernels with skin protection oxidize slowly, and the shelf life of roasted walnut kernels is shortened by about one-third due to high temperature treatment. Removing moldy and damaged particles during pre-treatment can reduce the risk of pollution.

4. Humidity control

High humidity in the freezing environment can easily cause ice crystal condensation. When the moisture content of walnut kernels exceeds 5%, they tend to become soft and sticky after thawing. Food desiccants can be placed inside sealed bags, or surface moisture can be removed by using kitchen paper first.

5. Variety characteristics

Thin shell varieties have a higher fat content and are more prone to spoilage, while thick shell varieties are relatively resistant to storage. Paper skin walnut kernels need to be consumed 1-2 months earlier than regular walnut kernels due to minimal residue on the outer shell. Organic planting products have a shortened shelf life of about 20% due to the absence of preservatives.

It is recommended to consume frozen walnut kernels within their shelf life and use them as soon as possible after thawing to avoid secondary freezing. The freezing date can be marked in advance to manage the inventory. It is better to use it directly without unfreezing when baking or cooking Congee. If the color darkens, oil or mold stains appear, it should be discarded immediately. Seal it promptly after daily use to avoid mixing it with other strongly scented foods. Eating foods with high vitamin E content together can help slow down the rate of oxidation.