Estimation of technological properties of nut meals and their effect on the quality of emulsion for butter biscuits with liquid oils

Abstract

We have examined the technological properties of cedar nut meal (CNM) and walnut nut meal (WNM). It was established that nut meals are the highly dispersed powders whose degree of dispersion exceeds that of wheat flour. The size of 69 % of CNM is up to 40 µm, 72 % of WNM, and only 35 % of flour. Compared with wheat flour, nut meals exposed to temperatures of 20...60 °C are characterized by better water-retaining capacity. When exposed to temperatures of90 °C, meals and flour have close values for water-retaining capacity. It was noted that nut meals are better at emulsifying liquid fats than solid that are traditionally used in the technology of butter biscuits (margarine and butter). It is shown that meals are characterized by high fat-retention capacity (FRC) relative to liquid vegetable oil. It is noted that the value of FRC for nut meals in the temperature range 20...60 °C increases by 1.9 times; in the range 60...80 °C, FRC of the examined samples almost does not change; and when exposed to temperatures of 100...140 °C, it starts to decrease. We have studied the quality of emulsions for butter biscuits for the case when 30 % of margarine are replaced with liquid vegetable oil while adding various amounts of nut meals. It was established that stability of the emulsion in which 30 % of margarine were replaced with liquid vegetable oil is 37.5 % less compared to control based on margarine. The introduction of CNM and WNM improves the stability of such an emulsion. It was noted that the samples of emulsion with the addition of 40 % and 50 % of CNM and WNM in terms of the value for an indicator of stability are maximally close to the control whose fat base was margarine. This is confirmed by the results from studying the dispersion, the effective viscosity of emulsions, and by results from microscopy. The obtained results are of practical significance in order to improve the technology of butter biscuits towards a partial substitution of margarine with liquid oils. That would improve the nutritional and biological value of butter biscuits.