Packaging
There are several factors to consider in packaging frozen vegetables, which include protection from atmospheric oxygen, prevention of moisture loss, retention of flavour, and rate of heat transfer through the package (Arthey, 1996). There are two basic packing methods recommended for frozen vegetables: dry pack and tray pack.
In the dry pack method, the blanched and drained vegetables are put into meal-sized freezer bags and packed tightly to cut down on the amount of air in the package. Proper headspace (approximately 2 cm) is left at the top of rigid containers before closing. For freezer bags, the headspace is larger. Provision for headspace is not necessary for foods such as broccoli, asparagus, and brussels sprouts, as they do not pack tightly in containers (Kendall, 2002).
In the tray pack method, chilled, well-drained vegetables are placed in a single layer on shallow trays or pans. Trays are placed in a freezer until the vegetables become firm, then removed. Vegetables are filled into containers. Tray-packed foods do not freeze in a block but remain loosely distributed so that the amount needed can be poured from the container and the package reclosed (Kendall, 2002).
The technical approach of chapter 1 focuses mainly on the large scale freezing industry. However, it is important to highlight that all preliminary steps before freezing food products are quite similar whether on a large or small scale. Furthermore, chapter 3 focuses more on the more suitable approach for small food freezing industry.