Inactivation of Lactobacillus plantarum WCFS1 during spray drying and storage assessed with complementary viability determination methods

Quantitative Determination of Biogenic Element Contents and Phytochemicals of Broccoli (Brassica oleracea var. italica) Cooked Using Different Techniques

In this study, the effect of different cooking techniques on broccoli moisture, total phenolic, total flavonoid, and radical scavenging capacity results, polyphenol contents, and their quantitative values was investigated. The total phenolic quantities of fresh and cooked broccoli samples were assessed to be between 36.32 (conventional boiling) and 423.39 mg GAE/100 g (microwave heating). The radical scavenging activities of the broccoli samples were reported between 2.55 (conventional boiling) and 4.99 mmol/kg (microwave heating). In addition, catechin and rutin quantities of the fresh and cooked broccoli samples were measured to be between 2.24 (conventional boiling) and 54.48 mg/100 g (microwave heating), and between 0.55 (conventional boiling) and 16.33 mg/100 g (microwave heating), respectively. The most abundant elements in fresh and cooked broccoli samples were K, Ca, P, S, and Mg. The results showed some changes depending on cooking techniques compared to the control. The bioactive properties of broccoli samples cooked by means of conventional boiling, boiling in vacuum bag, and high-pressure boiling were established to be lower compared to the fresh sample. Catechin, 3,4-dihydroxybenzoic acid, rutin, and gallic acid were the key phenolic compounds of fresh and cooked broccoli samples. The phenolic components of broccoli were significantly affected by the applied cooking techniques. The highest protein in broccoli samples was determined in the broccoli sample cooked by boiling in a vacuum bag. There were statistically significant changes among the mineral results of broccoli cooked with different cooking methods.

Microencapsulation of Lactobacillus rhamnosus ATCC 7469 by spray drying using maltodextrin, whey protein concentrate and trehalose

This study aimed to microencapsulate Lactobacillus rhamnosus (L. rhamnosus) ATCC 7469 with whey protein concentrate (WPC), maltodextrin and trehalose by spray drying and to assess the impact of microencapsulation on cell viability and the properties of the dried powders. Spray-drying conditions, including inlet air temperature, air flow rate and feed pump, were fixed as independent variables, while probiotic survival, moisture content, water activity and effective yield were established as dependent variables. The survival of encapsulated L. rhamnosus by spray drying was optimized with response surface methodology, and the stability of the powder was assessed. The optimum spray-drying conditions were an inlet air temperature, air flow rate and feed pump rate of 169 °C, 33 m³·h^-1 and 16 mL·min^-1, respectively, survival of 70%, air aspiration of 84% and outlet air temperature of 52 °C, achieving an overall desirability of 0.96. The physicochemical and structural characteristics of the produced powder were acceptable for application with regard to residual water content, hygroscopicity, water activity, and particle size. The results indicated that a protein-trehalose-maltodextrin mixture is a good wall material to encapsulate L. rhamnosus, showing important thermal protection during the drying process and increasing survival. However, a decrease in this capacity is observed at an air outlet temperature of approximately 101 °C. The possible effects of the wall materials and the drying conditions on survival are also discussed.