This study investigated the surface tension and foaming properties of the hot-water extracts of pumpkin leaf and chickpea, as well as the effects of the plant hot-water extracts on white pan bread baking. Propylene glycol alginate (PGA), a synthetic emulsifier widely used in bakery, was used as a control. Pumpkin leaf water extract showed lower surface tension and comparable foaming capacity, compared with chickpea water extract and PGA solution when total solid  0.15% (w/w). Chickpea water extract showed the highest foam stability when total solid  0.15% (w/w). The dough was found to have a weak gel structure, and its viscoelastic properties were not significantly influenced by adding 0.05% or 0.15% (w/w) (based on total solid content) plant water extracts or PGA. The specific volume of the bread increased, and the baking loss was reduced by adding the two plant water extracts of total solid 0.15% (w/w). The hardness and chewiness of the bread crumb were reduced to a level comparable to the crumb containing 0.05% (w/w) PGA. The results showed that the pumpkin leaf water extract could be an effective natural emulsifier with a high phenolic content for bakery products.

Powderization is a promising way to enhance the usability of fruits. Persimmon is one of the most popular fruits in Korea, but its usability is quite limited due to its high moisture content and seasonal availability. The objective of this study is to powderize a persimmon extract by spray drying and to examine the effects of resistant maltodextrin (RMD) and its mixtures with gum arabic (GA) as biopolymeric drying aids on the yield, moisture content, and water activity of resulting persimmon powder. Maltodextrin (MD) and its mixtures with GA were also used for comparison purpose. The feed solutions for spray drying were prepared by adding RMD, MD, GA or their mixtures (RMD:GA=9:1, 8:2, 7:3, 6:4, and 5:5; MD:GA=5:5 and 1.7:8.3) to persimmon extract at a concentration of 30% (w/w) (40% (w/w) total solid). The inlet temperature, air flow rate, atomizing pressure, and feeding rate for spray drying were set as 140 °C, 0.40 m3/min, 100 kPa, and 270 mL/h, respectively. Among the three biopolymers, the highest drying yield (51%) was obtained when RMD was added, followed by GA-added (34%) and MD-added (21%) powders. However, the RMD-added powder was sticky and caused bag filter blockage. Among the biopolymer mixtures, the highest yield (56%) was obtained when the RMD–GA mixture (7:3) was added, and no serious powder stickiness was visually observed. The powder prepared with RMD or MD only yielded very low values of moisture content (1.5-2.0%) and water activity (0.09-0.10), and the values increased when GA was added together. This study demonstrated that the RMD–GA mixture is an effective drying aid for the spray drying of persimmon extract, which is highly sticky and not able to be spray-dried alone.