Processing of raspberries to dried fruit foam: impact on major odorants

Abstract

Application of an aroma extract dilution analysis (AEDA) to the volatiles isolated from raspberry fruits by solvent extraction and solvent-assisted flavour evaporation (SAFE) resulted in 40 odour-active compounds with flavour dilution (FD) factors between 1 and 4096. Among the most potent odorants were violet-like smelling β-ionone (FD factor 4096), fruity smelling methyl 3-methylbutanoate (1024), baked-apple-like smelling β-damascenone (1024), raspberry-like smelling raspberry ketone (128), and floral, raspberry-like smelling α-ionone (64). These five odorants were subsequently monitored during processing of raspberry fruits to freeze-dried fruit foam. Major losses occurred during separation of the pulp from the seeds and during the final freeze-drying step. It was shown that the pulp fraction directly adherent to the seeds contained higher odorant concentrations than the outer parts of the pulp, thus losses associated with the removal of the seeds can be minimised by increasing the efficiency of the separation. Losses associated with the freeze-drying process could be reduced using microwave-assisted freeze drying instead of conventional freeze drying. Higher amounts of potato protein and maltodextrin used as foaming agent and foam stabiliser, respectively, reduced the odorant recoveries in the dried foams. Only a small part of the odorants not recovered in the dried fruit foams was found in the condensate.

The Role of Maltodextrin Concentration in Maintaining Storage Stability of Dried Fruit Foams Texturized Using Plant Protein–Polysaccharide Blends

“…A 100 g sample of fresh foam for each experiment was gently spread at a height of 1.04 ± 0.16 cm into a glass dish 190 mm in diameter (VWR International GmbH, Darmstadt, Germany) and stored at −80 °C for 24 h prior to drying. The samples were dried according to the drying procedure established in our previous research [ 1 , 16 , 17 ]. In brief, the conditions were as follows: the condenser temperature was −50 °C, the microwave power was applied using the pulsed heating mode at 1.0 W g −1 , controlled according to the product’s surface temperature.…”

“…The sensory panelists, consisting of 10 trained assessors with experience in sensory analyses, attended several training sessions. According to Lang et al [ 16 ], regarding the odor-active compounds in raspberry, the panelists created descriptive terms for the fruit pulp which were used for the descriptive analyses. The resulting five aroma terms are shown in Table 1 .…”

Effect of Processing Methods and Storage Time on the Content of Ascorbic Acid in Berries

“…Помимо абсолютного содержания АК, немаловажное значение имеет динамика изменения этого показателя. С одной стороны, этот показатель влияет на установление сроков годности ягод, с другой -устанавливает определенные ограничения на способы использования ягод после размораживания [4,27,36].…”