Alfred Trappey II, Wilson, Paul W., Johnson, Charles E. | 5/6/2005 6:37:35 PM
A freshly prepared mayhaw fruit juice should correspond to the composition of the fruit selection from which it has been prepared. If the juice extraction method has been effective, there should not be significant differences between the fresh juice and the original fruit. However, the processing of mayhaw fruit can change its juice composition, especially when heat-treated. Additionally, the mayhaw fruit selection used for juice production, stage of fruit maturity at the time of harvest as well as cultural variables can all produce variations and inconsistencies in the initial composition of the expressed mayhaw fruit juice. Here are results of a study of juice preparation using only one variety of mayhaw, the “Texas Star.”
Six extraction methods were evaluated: steam extraction using whole fruits, steam extraction using whole fruits with added pulp juice, cold-press extraction using whole fruit, cold-press extraction using finely ground fruit pulp, hot press extraction using finely ground fruit pulp and hot press extraction using finely ground fruit pulp incorporating a commercial pectolytic enzyme as a pretreatment aid before pressing. Quantitative results on mayhaw fruit juice composition after the initial expression when using either fresh or frozen fruit were significantly different among each extraction method used.
Some aspects of mayhaw fruit juice, such as color, are entirely a consequence of processing methodology. Study results show that comminution or milling, fruit pulp holding temperature, type of extraction method and condition of fruit (fresh or frozen) singularly and collectively had a significant influence in determining the final composition and color of fresh mayhaw juice. Pectolytic enzymes, when used properly, will significantly increase juice extraction yields of both fresh and frozen mayhaw fruit.
For this study, mayhaw fruit juice was extracted with the use of a rack and frame hydraulic press, which works well with small quantities of fruit. However, a disadvantage of this system is the inability to mix the fruit (whole or ground) during cold-press extraction of either fresh or frozen fruit. Study findings showed significant inconsistency in juice efficacy. This is primarily due to pockets of unpressed fruit that became trapped and unavailable for juice expression in the rack and frame hydraulic press system.
To optimize mayhaw juice processing, specific variables must interact effectively. For each of the six extraction methods, these variables were: mayhaw fruit quality, fruit pretreatment (freezing as a press aid), type of fruit preparation (whole or ground), the quality and type of juice desired (sugar to acid ratio), condition of mayhaw fruit at the time of comminution (texture), enzyme usage and temperature of the fruit pulp at the time of expression.
Handpicked mayhaw fruit is generally of good quality, but natural variations in the composition of mayhaw fruit, such as stage of maturity and cultural practices, will all produce significant variations or inconsistencies in the composition of expressed juice.
With the growth of mechanical harvesting of mayhaw fruit, quality standards must be developed to limit the introduction of the following: contamination by debris (leaves, insects, dirt and twigs), damage of fruit, and inconsistencies in fruit maturity, all of which have to be sorted and removed before processing. From a producer’s perspective, minimum quality standards or grading guidelines must be established for large-scale mayhaw fruit purchase. On the processing end, impurities need to be identified and removed before milling and pressing, particularly sun-scaled mayhaw fruit, rotten fruit and insect-damaged fruit. The quality of the fruit determines the problems that may occur during juice processing.
Research indicates that frozen storage of mayhaw fruit can be used effectively without lowering juice yield or quality. Processing of fresh mayhaw fruit in the future with the advent of mechanical harvesting may present scheduling problems because most mayhaw selections tend not to mature at the same time. Frozen storage would allow for an accumulation of inventory, thereby creating a consistent supply of fruit, since crop yields may vary considerably from year to year because of extremes in weather conditions.