The objective of this study was to characterize three different commercial (A, B and C) and two handmade (HM-AP, atmospheric pressure; HM-RP, reduced pressure) strawberry jams in relation to soluble solids, pH, total acid, total polyphenol, anthocyanin, color values, texture properties, and sensory evaluation. The soluble solid contents varied from 62.33 to 68.33 °Brix, and the pH ranged from 3.59 to 3.70. The color L and a values were the highest in the HM-RP strawberry jam (p<0.05). The total polyphenol contents of commercial jams A, B, and C were 56.10, 97.59, and 105.85 mg GAE/100 g, respectively, and those of the HM-AP and HM-RP of handmade jams were 156.13 and 189.94 mg GAE/100 g. The anthocyanin contents of A, B, and C commercial jams were 1.51, 0.95, and 0.80 mg/100 g, respectively, and those of the HM-AP and HM-RP handmade jams were 2.64 and 9.16 mg/100 g. The phenolic contents of the HM-RP jam were significantly much higher than those of the other jams. The hardness ranged from 5.67×103 (HM-AP jam) to 41.91×103 (jam B) dyne/cm2, the jelly strength ranged from 40.08 (HM-AP jam) to 180.33 (jam B) dyne, and the strength ranged from 83.84 (jam C) to 302.93 (jam B) g. The sensory evaluation of the color, flavor, sweetness, sourness, viscosity and overall acceptability of the HM-RP jam showed higher values than those of the other jams. Especially, the highest value of the color score was found in the HM-RP jam. The electon donating abilities of jams A, B, and C and of the HM-AP and HM-RP jams were 44.27, 41.70, 53.06, 69.08, and 73.21%, respectively. These results indicated that the HM-RP strawberry jam prepared with reduced pressure using micro-oxygen technology was a good source of phenolic compounds, total polyphenols and anthocyanin, and had a high level of antioxidant activity.

• 정난정(강릉원주대학교 식품과학과) | Nan-Jung Jung
• 강윤한(강릉원주대학교 식품가공유통학과) | Yoon-Han Kang Corresponding author