Gurrieri S, Miceli L, Lanza C M, Tomaselli F, Bonomo R P, Rizzarelli E
Istituto per lo Studio delle Sostanze Naturali di Interesse Alimentare e Chimico-Farmaceutico, Sezione di Catania, CNR, Viale A. Doria 6, 95125 Catania, Italy.
J Agric Food Chem. 2000 Nov;48(11):5424-31. doi: 10.1021/jf9907844.
In this work, Sicilian cultivars of prickly pear (Opuntia ficus indica) were partially characterized from a chemical point of view, and the possibility of long-term storage of their juice was investigated. The acidity of the prickly pear juice turned out to be very low (0.02%) and the pH very high (6.4-6.5) if compared with values found in other common fruit juices. In the perspective of processing and storage conditions according to Italian law, the acidity has been corrected by adding the proper amount of tartaric and/or phosphoric acid. The sugar content (mainly glucose and fructose) is very high (11-12%), and also L-ascorbic acid is present in considerable amount (31-38 mg/100 g). Among the transition metals, a high content of manganese(II) (1.7-2.9 ppm) and good amounts of iron(III) (0.6-1.2 ppm) and zinc(II) (0.3-0.4 ppm) were found. In particular, such ions appear to be present mainly in the thick skin of the fruit or "trapped" inside the pulp. Pectin methylesterase (PME) seems to be present in very small amount and/or is not highly active. Furthermore, PME activity decreases considerably after the necessary adjustment of the pH and the thermal treatment requested for long-term storage. After approximately 2 months, none of the juices prepared was affected by noticeable sedimentation of the pulp. Finally, different samples of prickly pear juice were sensorially analyzed, employing descriptors such as color, aroma, viscosity, acidity, sweetness, and off-flavors. The results obtained can be considered very satisfactory, and the juice has been widely appreciated when compared with other products commonly available on the market such as pear and peach juices.
在这项工作中，从化学角度对西西里品种的仙人掌果（仙人掌属）进行了部分特性分析，并研究了其果汁长期储存的可能性。与其他常见果汁的值相比，仙人掌果汁的酸度非常低（0.02%），pH值非常高（6.4 - 6.5）。从意大利法律规定的加工和储存条件来看，已通过添加适量的酒石酸和/或磷酸来校正酸度。糖含量（主要是葡萄糖和果糖）非常高（11 - 12%），而且L - 抗坏血酸的含量也相当可观（31 - 38毫克/100克）。在过渡金属中，发现锰（II）含量很高（1.7 - 2.9 ppm），铁（III）（0.6 - 1.2 ppm）和锌（II）（0.3 - 0.4 ppm）的含量也较高。特别是，这些离子似乎主要存在于果实的厚皮中或“被困”在果肉内部。果胶甲酯酶（PME）似乎含量极少和/或活性不高。此外，在进行长期储存所需的pH值调整和热处理后，PME活性大幅下降。大约2个月后，所制备的果汁均未受到明显的果肉沉淀影响。最后，对不同的仙人掌果汁样品进行了感官分析，使用了颜色、香气、粘度、酸度、甜度和异味等描述词。所获得的结果可以认为非常令人满意，与市场上常见的其他产品如梨汁和桃汁相比，该果汁广受好评。
