Mitigation of acrylamide and hydroxymethylfurfural in biscuits using a combined partial conventional baking and vacuum post-baking process: Preliminary study at the lab scale

• Combined conventional and vacuum baking process was introduced for biscuits.
• Combined process lowered the heat load applied to biscuit during baking.
• Applying vacuum during baking provided faster drying of biscuits.
• Biscuits baked by the combined process were free of acrylamide and HMF.
• Safer biscuits were obtained with similar textural properties, but lighter color.

A combined conventional and vacuum process was introduced as a new baking technology to mitigate acrylamide and 5-hydroxymethylfurfural (HMF) in biscuits in this study. Firstly, these processes were compared for acrylamide and HMF formations, drying rate, and browning development at different temperatures. Acrylamide concentrations in biscuits attained during vacuum baking were significantly lower than those attained during conventional baking at all temperatures studied (p < 0.05). Besides, there was no HMF formation in biscuits during vacuum baking. Comparing to conventional baking, heating under lower pressure provided lower time–temperature profile with slightly accelerated evaporation of water in dough. However, development of surface browning was lacking in vacuum baked biscuits. Secondly, combinations of conventional and vacuum processes were used to produce biscuits. The dough that was partially baked at 220 °C for 2–4 min under conventional conditions was post-baked under vacuum for accelerated drying at 180 °C and 500 mbar for 4–6 min until the desired final moisture content was attained. Doing so, exposure of biscuits to higher temperatures for longer time, which was essential to facilitate the chemical reactions leading to thermal process contaminants, was prevented. The combined process formed no acrylamide or HMF (< LOQ) in biscuits. It was considered as a promising alternative to produce safer biscuits for targeted consumers like infants.Industrial relevanceThe study has been performed in the course of the FP7 project PROMETHEUS that aimed to develop new or alternative technologies for the mitigation of thermal processing contaminants in foods. Mitigation of thermal processing contaminants, especially acrylamide in heated foods has been an intensive area of research in the last decade. It was confirmed repeatedly by many researchers that increasing processing temperature also increases the formation rates of those undesired compounds. Therefore, one approach to mitigate them is to lower temperature during processing. However, this is not viable practically, because lowering temperature requires longer time to achieve desired final moisture contents in the final product. The approach presented in this manuscript takes the advantage of faster drying of biscuits during heating under vacuum. Using the combination of conventional par-baking with vacuum post-baking seems to produce safer biscuits than the conventional counterparts in terms of their acrylamide and HMF contents. At industrial level vacuum application has been used in bread processing for cooling purposes. In that case, breads are cooled rapidly after baking in semi-continuous vacuum chambers. As implementation of vacuum application into the process has already been practiced, it is likely that partially baked biscuits could be post-baked for short times in semi-continuous vacuum chambers maintained at specified conditions. To the best of our knowledge, such combined baking process has not been investigated to date for the mitigation of thermal processing contaminants in biscuits. So, it is believed that the results of present manuscript would be interesting for bakery industry dealing with the above-mentioned safety problem, but also for the readers of this journal.