Download (1MB) | Preview
Item Type: Tesi di dottorato
Uncontrolled Keywords: soymilk, okara
Date Deposited: 07 Dec 2011 16:44
Last Modified: 17 Jun 2014 06:03


In the context of space mission designing, physical and chemical systems which regenerate the resources with production "in situ" of air, food and water are increasing their importance. The MELiSSA (Micro-Ecological Life Support System Alternative) project aims at developing of an artificial ecosystem of microorganisms and higher plants able to support the life of a crew during long-term space missions. Particular attention has been given to the choice of plant species and technologies for their processing. Among several candidate species, potato, soybean and two wheat species were selected. Soybean (Glycine max (L.) Merr.) is an important crop wordwide because of its high nutrient content and because of the main ways it can be processed. Within a closed system for a space mission, yield, energy consumption, sensorial acceptability and numerous other factors must be taken into account. For these reasons, the simultaneous production of soymilk and okara was considered optimal: it allows high nutrient recovery without excessive energy consumption. In order to identify optimal parameters for soybean processing into milk and okara, water for soaking at room temperature was chosen: it provides long times but low nutrient leaking in the water and no energy expenditure. Optimal processing parameters were seeds milling in water at room temperature and extraction by 30 min boiling; next steps were filtration to separate aqueous extract from the pulp and milk sanification by boiling for15 min. Regarding sensorial aspects, consumers do not always appreciate soymilk, but it is possible to improve taste by adding sugar and vanilla. A study with non-expert panelists showed that salt and vanilla sugar addition fails to mask the typical bean aroma but it can improve taste up to global levels of pleasantness comparable to market soymilk. The possibility of soybean production cycle shortening was evaluated: for this purpose effects on seeds and transformed products were studied. Harvest of immature seeds results great management and economic benefits and, from a nutritional point of view, it is possible to obtained processed products with lower phytic acid content. On the other hand, it is well known that the accumulation of dry matter and nutrients in soybeans seeds increases with advancing of maturation steps. For dry matter, this trend was mitigated with transformation but for fat and protein the highest concentration was observed in soymilk and okara from seeds at complete maturation so, optimal harvest moment within a Life Support System is commercial ripeness. Based on this preliminary information, nutritional and compositional comparison, among four different cultivars of soybean seeds and their derived products were performed. Influence of hydroponic cultivation in controlled environment (simulation of a Life Support System in the space) was evaluated, too. Hydroponic cultivation in controlled environment is not only a method to produce food in space, but also a system to increase lipid, fiber and mineral accumulation in soy seeds. Hydroponic cultivation in controlled environment determined different performances compared to open field cultivation and, for this reason, selecting optimal cultivar, only data from experimental cultivation must be considered. In particular during soymilk and okara production, seeds cultivation system did not significantly modify aqueous extract composition but only residue pulp characteristics. The choice of the best cultivar will be contextualized within the diet of the astronauts: good protein and fiber values were observed in transformed products from Atlantic seeds but, if you need a higher fat content, you will choose other cultivars such as Cresir or Regir. After this stage of the study about food production and preparation on Earth, a second phase with the study of technology in the absence of gravity and the evaluation of space environment effect on biological processes will perform.

Actions (login required)

View Item View Item