Almond Processing Effects

Natural almonds may be processed into different forms (blanched, roasted, sliced, slivered, diced or ground) for ingredient or snacking applications. These products receive heat and/or size reduction treatments. The heat treatments may initiate some chemical reactions in the almonds. Size reduction treatments will increase the amount of surface area exposed to air. Both treatments will have some impact on the shelf stability of the processed almond products. Cut and roasted almond forms will have a shorter shelf life than natural whole almonds. To preserve the shelf life of processed forms, special attention should be paid to processing parameters (e.g., temperature, time) and post-process handling. Roasting is a common process that has the greatest impact on quality.

Roasting optimization.

Roasting is a heat process that is used to modify the texture, color and flavor of natural California almonds. Roasted almonds have a crunchier texture, a browner color and a desirable roast-flavor profile. Almond kernels, with skin or blanched, can be roasted by hot air (dry roasting) or in hot oil, depending on your application needs. Dry-roasted almonds are typically used in chocolates, confectionary products, breakfast cereals and baked goods, and increasingly for snacking. Oil-roasted almonds are typically used in ice cream and for snacking. In-shell almonds can also be dry-roasted for snacking applications.

Almonds are commonly roasted at 265 to 320°F (~130 to 160°C). Roasting at the low to mid temperatures of 265 to 293°F (~130 to 145°C) helps to preserve the almond microstructure and maximize product shelf life. Various roasting temperature and time combinations can be utilized to obtain light-, medium- or dark-roasted almonds. In most cases, the same degree of roast (in terms of color development) can be achieved at different temperatures by adjusting the roasting time: Longer times are required at the lower roasting temperatures, and shorter times at the higher roasting temperatures. To choose optimal roasting processes for California almonds, consider the desired color and flavor as well as the shelf life and quality aspects.

The critical requirements of a roasting process for almonds are:

• Delivering uniform heat treatment;

• Providing consistent quality in nut color, texture and flavor;

• Preserving nut integrity, subcellular microstructure and appearance;

• Cooling roasted nuts immediately after heat treatment; and

• Packing roasted nuts promptly after cooling with high-barrier packaging to limit oxidation during storage.