Application of Microwaves to Reduce Checking in Low-Fat Biscuits: Impact on Sensory Characteristics and Energy Consumption

Abstract

The use of microwaves (MWs) has been proposed as an energy-efficient method for reducing checking. Along with understanding moisture distribution, it is essential to consider structural characteristics to explain how MWs reduce checking. The influence of MWs on these characteristics depends on the food matrix's dielectric and viscoelastic properties, which vary significantly between fresh and pre-baked dough. This study investigates the effects of MW treatment applied before (MW-O) or after conventional oven baking (O-MW) on low-fat biscuits that are prone to checking. Color (CIELab), thickness, moisture content and distribution, checking rate, texture, sensory properties, energy consumption and baking time were analyzed. The findings suggest that MWs reduce checking rate by eliminating internal moisture differences, while also changing structural properties, as evidenced by increased thickness and hardness. MW-O eliminated checking (control samples showed 100%) but negatively affected color, texture (increased hardness and breaking work), and sensory quality. The O-MW checking rate (3.41%) was slightly higher than in MW-O, probably due to the resulting different structural properties (less thickness, less hardness and breaking work). O-MW biscuits were the most preferred by consumers (54.76% ranked them first), with color and texture close to the control samples. MW-O reduced total energy consumption by 16.39% and baking time by 25.00%. For producers, these improvements could compensate for the lower biscuit quality. O-MW did not affect energy consumption but reduced baking time by 14.38%. The productivity improvement, along with the reduction in checking and the satisfactory sensory quality, indicates that O-MW could be beneficial for the bakery sector.

Keywords: baking; biscuit breaking; cereal-based products; cookies; drying; emerging processing; energy cost; mechanical properties.

Figure 1

Biscuit hardness (g) (a) and breaking work (g s) (b) as a function of baking method, O (solid), O-MW (scratched) and MW-O (pointed), after one day of storage. Means ± 95 CI (n = 24). Different letters denote significant differences for each parameter (p < 0.05) based on the baking process.

Figure 2

Values for odor, appearance, flavor, texture and overall impression of the biscuits based on the baking method, O (solid line), O-MW (dashed line) and MW-O (dotted line), as evaluated by the consumer panel (n = 42).

Figure 3

Ranking of the biscuits (sorting test) based on the baking method, O (solid), O-MW (scratched) and MW-O (pointed), according to the consumer panel (n = 42). Means ± 95 CI. Different letters denote significant differences between samples (p = 0.05).