Stability of aspartame and neotame in pasteurized and in-bottle sterilized flavoured milk

• SPE method was standardized for isolation of aspartame and neotame in flavoured milk.
• Pasteurization resulted in ∼40% and 8% loss of aspartame and neotame, respectively.
• Storage (4–7 °C/7 days) caused ∼15% and 4% loss of aspartame and neotame respectively.
• Sterilization caused complete loss of aspartame but ∼50% of neotame remained intact.
• During storage (30 °C/60 days) neotame content decreased from 50.36% to 8.67%.

Analytical high performance liquid chromatography (HPLC) conditions were standardized along with the isolation procedure for separation of aspartame and neotame in flavoured milk (pasteurized and in-bottle sterilized flavoured milk). The recovery of the method was approximately 98% for both aspartame and neotame. The proposed HPLC method can be successfully used for the routine determination of aspartame and neotame in flavoured milk. Pasteurization (90 °C/20 min) resulted in approximately 40% loss of aspartame and only 8% of neotame was degraded. On storage (4–7 °C/7 days) aspartame and neotame content decreased significantly (P < 0.05) from 59.70% to 44.61% and 91.78% to 87.18%, respectively. Sterilization (121 °C/15 min) resulted in complete degradation of aspartame; however, 50.50% of neotame remained intact. During storage (30 °C/60 days) neotame content decreased significantly (P < 0.05) from 50.36% to 8.67%. Results indicated that neotame exhibited better stability than aspartame in both pasteurized and in-bottle sterilized flavoured milk.