Packaging of Rice Food in Retort Pouches

 A retort sachet consists of a plastic pouch and aluminum foil with 3 or 4 wide closures, usually made by aseptic processing, which allows the sterile packaging of a wide variety of beverages, from water to complete, cooked and thermally stabilized meals such as prepared meals that can be eaten cold, reheated by immersion in hot water, or easier and cheaper to ship using a heater. With this technique, the first prepared foods (raw or cooked) are wrapped in a retort pouch. The pouch is then heated under high pressure in retorts or autoclaving machines at 240-250 ° F (116-121° C) for several minutes. This procedure reliably kills all common microorganisms and thus prevents their spoilage.

Rice is considered a semi-aquatic annual plant, although it can survive as a perennial in the tropics or subtropics. It can grow in a variety of water and soil regimes, from prolonged deep-water flooding to dry lands on mountainous slopes. Today, rice is grown in more than 100 countries from the 53rd to the 40th parallel and from sea level to more than 3,000 m above sea level.

The retort pouch is a flexible, heat-sealable flat container that can withstand the high temperatures (121° C) required for pressure processing of rice and other low-acid foods. This container represents an alternative packaging system to conventional metal cans and cups, in Japan alone more than 750 million pouches of food are consumed per year.

The most commonly used retort pouch is a three-layer laminate composed of polyester, aluminum foil, and polypropylene. Polyester, typically 0.0005 inches (0.0127 mm) thick, serves as the outer protective layer due to its strength and resistance to abrasion and flexure. An intermediate layer of aluminum foil is used to extend the useful life of the product by acting as a barrier against the passage of light, water and oxygen. The thickness of the film layer can vary depending on the intended application (0.00035-0.0007 inches or 0.0089-0.0179 mm). The polypropylene inner layer provides an excellent food contact surface due to its inert properties.

This material was approved by the FDA in 1977 for use only at retort temperatures of 121 ° C or less. The film in the pouch is supplied to the processor in the form of rolls or in the form of pre-formed pouches. When roll material is used, the pouch forming process in the food factory is carried out by continuous forming, filling and sealing equipment. Current commercial pouches are 5 to 12 ounces of product, generally enough for a single serving. Larger institutional pouches are also available to hold a volume comparable to that of a can.

The retorted pouch rice was prepared by hermetically sealing cooked rice in laminated plastic and aluminum foil lined plastic pouches and by heat treatment at 120 ° C. Shelf life is 6 months at room temperature. The consumer immerses the intact pouch in hot water for 10 to 15 minutes (or transfers the contents of the foil pouch to a plate and microwaves it for 1 to 2 minutes). Cooking for 10 minutes increases the degree of gelatinization of the horned rice by 55% before cooking it to 90%. Freshly cooked japonica rice has a gelatinization rate