The Impact of Bentonite Fining on Apple Juice Clarity and Sodium Content

Abstract

In the experiment, four calcium bentonites (Ca bentonites) with different sodium contents in their activator were used for the pretreatment fining before the pasteurization of apple juice. The percentages of sodium carbonate in the activator of bentonites were 0% (B-0), 30% (B-30), 50% (B-50) and 70% (B-70). For the determination of correlation between bentonite dosage and juice turbidity after fining, the apple juice was treated with the following dosages: +40 g/hL, +50 g/hL, +60 g/hL, +70 g/hL and +80 g/hL. Bentonites with added sodium in the activator achieved much better juice clarification compared to pure Ca bentonite. Better clarification of apple juice was obtained by bentonites with the higher sodium content in the activator and also in treatments with higher dosages (g/hL). All bentonites with added sodium in activator released significantly more sodium into the juice (6.7– 8.4 mg/L) compared to the control and pure Ca bentonite (3.2–3.4 mg/L). At higher doses of bentonite, the increase in sodium release into the juice was greatest with bentonite B-70. Bentonite with a small addition of sodium in the activator (B-30) was the best compromise in terms of juice clarification and sodium release.Vpliv čiščenja z bentonitom na bistrost in vsebnost natrija v jabolčnem soku. V poskusu smo za bistrenje jabolčnega soka pred pasterizacijo uporabili štiri kalcijeve bentonite (Ca bentonit) z različno vsebnostjo natrija v aktivatorju. Deleži natrija v aktivatorju so bili naslednji: 0% (B-0), 30% (B-30), 50% (B-50) and 70% (B-70). Za določitev korelacije med odmerkom bentonita in motnostjo soka po bistrenju smo uporabili različne odmerke: +40 g/hL, +50 g/hL, +60 g/hL, +70 g/hL in +80 g/hL. Bentoniti z dodanim natrijem v aktivatorju so dosegli veliko boljše bistrenje soka v primerjavi s čistim Ca bentonitom. Jabolčni sok se je bolje bistril pri bentonitih z višjim deležem natrija v aktivatorju ter hkrati ob višjih odmerkih (g/hL). Vsi bentoniti z dodanim natrijem v aktivatorju so sprostili bistveno več natrija v sok (6,7–8,4 mg/L) v primerjavi s čistim Ca bentonitom (3,2–3,4 mg/L). Pri večjih odmerkih bentonita je povečanje sproščanja natrija v sok največje pri bentonitu B-70.Bentonit z majhnim dodatkom natrija v aktivatorju (B-30) je najboljši kompromis v smislu bistrenja soka in sproščanja natrija.