Your original sentence, “Hydrocolloids still play an important role as carrier agents…” is acceptable, but it would be better to be more specific, for example:
“Maltodextrin (MD), a type of hydrocolloid, acts as a carrier agent that helps retain bioactive compounds such as phenolic compounds and anthocyanins during foam-mat freeze drying (Fauziyah et al., 2022).”
Your original sentence, “Hydrocolloids still play an important role as carrier agents…” is acceptable, but it would be better to be more specific, for example:
“Maltodextrin (MD), a type of hydrocolloid, acts as a carrier agent that helps retain bioactive compounds such as phenolic compounds and anthocyanins during foam-mat freeze drying (Fauziyah et al., 2022).”