Tomasz Jeliński

Physical Properties of Buckwheat Water Biscuits Formulated from Fermented Flours by Selected Lactic Acid Bacteria

Abstract The growth of lactic acid bacteria during liquid-state fermentation of buckwheat flour and changes in pH during the process were analyzed. Eight strains of Lactobacillus were selected as the most active strains used to obtain new fermented flours. Physical properties of buckwheat water biscuits formulated from these fermented flours were studied. The hardness of freshly prepared biscuits was affected by the lactic acid bacteria applied, with its highest value noted for the water biscuits made of buckwheat flour fermented by L. plantarum IB. Significantly greater differences in hardness values of water biscuits were noted after 24 h storage. Moreover, water biscuits made of the fermented flours were lighter and had a higher browning index as compared to the control biscuits prepared from unfermented buckwheat flour. The obtained results demonstrate the feasibility of selecting lactic acid bacteria for the fermentation of buckwheat flour focusing on some physical properties of the water biscuits.

Digital Image Analysis — Essence and Application in Cereal Science

Sight is the most important sense of a human allowing him to perceive the surrounding world. Size, shape, structure and colour of examined objects are easily recognised by human eye and brain and simultaneously verify whether they correspond to the standard. Interpretation of images registered solely by the sight is somehow limited by the observer’s perception. Increased number of objects and their mobility resulted in difficulties of proper interpretation of human observations. Moreover, the eyes become tired quite fast, thus their ability to differentiate selected features of the object decreases.

The Effect of Seed Size and Microstructure on Their Mechanical Properties and Frictional Behavior

The seeds of grass pea were selected based on their size, hardness, and microstructure in order to examine their mechanical properties and friction coefficients versus mass. The size, shape, mass, and static friction coefficients of seeds were determined using adequate methods. Seed hardness was measured using compression methods, and it was described by typical and corrected fracture parameters. The microstructure of cotyledons and seed surfaces was viewed using scanning electron microscopy, and surface microimages were processed by digital image analysis. The length of the examined seeds ranged from 5.86 mm to 14.25 mm, their width ranged from 5.47 mm to 12.93 mm, thickness from 4.59 mm to 6.21 mm, mass from 0.110 g to 0.570 g, projected area from 28.55 mm2 to 148.73 mm2, and roundness from 1.060 to 1.126. The static friction coefficients for seeds of the examined accessions and varieties determined on steel, wood, rubber, and PVC surfaces were 23.4–33.3°, 24.4–37.2°, 29.6–50.4°, and 22.4–35.4°, respectively. For grass pea seeds of irregular size and shape, corrected fracture energy values (with regard to seed mass and volume) were proposed as a more robust parameter of seed hardness. The values of the static friction coefficient depend on both seed mass and the microstructural properties of seed surface digitalized with the involvement of image analysis techniques.