Effects of dynamic high-pressure (DHP) treatments with and without integration with heating on microbial stability, vitamin C concentration, color, sugar content, and pH of orange juice were studied and compared with those of the conventional thermal treatment. Freshly squeezed orange juice was heated at 90oC for 1 min or DHP-treated at 205 MPa and 20, 50, 60, or 70oC. The DHP treatment at 20oC without heating and the treatment at 50oC inactivated indigenous mesophilic aerobic microorganisms in orange juice by 4.2 and >7 log CFU/mL, respectively. The DHPtreated juice exhibited brighter color and higher vitamin C concentration and sugar content than the thermally treated juice, regardless of integration with heating. The DHP-treated juice demonstrated brighter color and higher sugar contents than untreated juice and thermally treated juice during storage at 4oC for 63 days. The results have demonstrated the potential of applying DHP treatments to pasteurize orange juice with increasing brightness and sugar content of the juice.

The methods for determining the diffusion parameters for the diffusion of d-limonene, a major volatile compound of orange juice, through a multi-layered food packaging material and predicting its absorption into the packaging material have been investigated. The packaging material used was the 1.5-mm thick multi-layered packaging material composed of high impact polystyrene (HIPS), polyvinylidene chloride (PVDC), and low density polyethylene (LDPE). Orange juice was placed in a cell where volatiles were absorbed in the sample package and kept at 23±2oC for 72 hr. The d-limonene absorbed in a 1.5-mm thick multi-layered food packaging material was analyzed by a solid phase micro-extraction (SPME). The absorption parameters for the absorption of d-limonene in the packaging material were determined and absorption of d-limonene into the packaging material was predicted using absorption storage data. The SPME desorption at 60oC for 1 hr resulted in the most sensitive and reproducible results. The diffusion coefficients of d-limonene in the packaging material and the partition coefficient at 23±2oC were approximately 1-2×10-12m2/s and 0.03, respectively. The absorption profile no earlier than 30 hr was fit well by a model derived from the Fick’s law.

Varied levels of mannitol at 0%, 3%, 6% and 9% were added to the commercial orange juice and physicochemical and sensory characteristics of the juice were investigated. Refractive index of control had 11.3˚Bx and the index was significantly increased to that of the 18.4˚Bx as the addition was increased to the 9% level(p〈0.05). The values of pH and the acidity did not show significant differences among varied levels of mannitol added samples. However, sensory characteristics of aroma and sweet flavor were significantly increased as the addition levels were increased showing the values of aroma, from 7.5 to 11.3, and those of sweet flavor from 5.0 to 11.9, respectively (p〈0.05). The 9% added level sample had significantly the lowest sour and astringent flavor values of 4.0 and 2.3, respectively.

Freshly squeezed juices were prepared using the domestic Chunggyun, Hanrabong, and imported oranges and physicochemical and sensory characteristics of the juices were investigated. The Chunggyun had significantly the lowest pH value of 3.35, and imported and Hanrabong showed the pH values of 3.82 and 3.93, respectively(p〈0.05). The refractive index of Hanrabong showed significantly the highest values of 14.7˚Bx (p〈0.05), and the samples of imported and Chunggyun did not show significant differences with indices of 12.5 and 12.2, respectively. The quantitative descriptive analysis(QDA) showed imported sample had significantly the highest values of sweet and sour aroma with values of 11.57 and 11.08, respectively. However, Hanrabong showed significantly the highest value of sweet flavor with value of 12.31. Consumer acceptance test represented the Chunggyun was the most accepted one but did not show any great differences in overall, appearances, and flavor among the samples.

Recoverable oil 농도별 처리에 따른 MOS(metal oxide sensor) 전자코를 이용한 향기 패턴 분석 결과 오일 함량이 증가함에 따라 제 1 주성분 값의 분포가 부근으로 이동하는 경향을 나타내었으며, 주성분 분석의 discrimination index가 89로서 첨가 농도에 따른 향기 패턴이 명확히 구별되고 있는 것으로 나타났다. 저장기간에 따른 향미 변화는 거의 없었으며 약간 감소하는 경향을 나타내었다. 저장기간에 따른