Centre Especial de Recerca Planta de Tecnologia dels Aliments, Departament de Ciència Animal i dels Aliments, XaRTA, TECNIO, MALTA-Consolider, Facultat de Veterinària, Edifici V, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Int J Food Microbiol. 2010 Jan 1;136(3):261-7. doi: 10.1016/j.ijfoodmicro.2009.11.011. Epub 2009 Nov 20.
The effect of ultra high pressure homogenisation (UHPH) at 100, 200 and 300 MPa on apple juice at two different inlet temperatures (4 and 20 degrees C) was studied. Raw and conventional heat treated (PA) apple juice was compared with UHPH treated juice after treatment and during 60 days of storage at 4 degrees C. The microbial quality was studied by enumerating aerobic mesophilic counts (AM), psychrotrophs (PS), moulds and yeasts (MY), lactobacilli (LB), enterobacteriaceae (EB), and faecal coliforms (FC). PA samples were below detection level (< or = -2 log cfu/mL) for all groups, the same as UHPH treated juices at 200 MPa and above but for around 1 log cfu/mL for AM. Those AM counts did not change during 60 days storage at 4 degrees C and proved to be spores. Juices treated at 100 MPa shown little reductions in microbial counts, and surviving microorganisms significantly increased their numbers during storage. This research work showed that non-thermal methods such a UHPH technology may give new opportunities to develop "fresh like" apple juice with a shelf-life equivalent to PA in terms of microbiological characteristics without affecting the product quality.
超高压均质（UHPH）在 100、200 和 300 MPa 下对两种不同进口温度（4 和 20°C）的苹果汁的影响进行了研究。将未经处理和经过常规热处理（PA）的苹果汁与经过处理的 UHPH 处理后的苹果汁进行了比较，然后在 4°C 下储存 60 天。通过计数需氧嗜温菌（AM）、嗜冷菌（PS）、霉菌和酵母（MY）、乳杆菌（LB）、肠杆菌科（EB）和粪大肠菌群（FC）来研究微生物质量。PA 样品的所有组均低于检测水平（<或= -2 log cfu/mL），与 200 MPa 及以上的 UHPH 处理的果汁相同，但 AM 的计数约为 1 log cfu/mL。这些 AM 计数在 4°C 下储存 60 天时没有变化，证明是孢子。在 100 MPa 下处理的果汁中，微生物计数的减少很少，存活的微生物在储存过程中显著增加了数量。这项研究工作表明，非热方法（如 UHPH 技术）可能为开发具有与 PA 相当的保质期的“新鲜”苹果汁提供新的机会，就微生物特性而言，而不会影响产品质量。
