Evaluation of physico-chemical characteristics of jujube kernel (Isfahan jujube)

Dissertation for Master's Degree

Field: Food Engineering

Treatment: Food Chemistry

Abstract:

Jujube species is one of the native species of different regions of Iran. The fruit of this plant is traditionally consumed in different regions of Iran. This fruit has very useful medicinal and edible properties. About 30% of the weight of the fruit is made up of its kernels. On average, the kernel of this fruit contains about 3.8% of oil. Considering the very valuable properties of jujube fruit, the purpose of this research is to evaluate the physicochemical characteristics of jujube kernels in the region of Isfahan province in terms of fatty acid composition and stability to oxidation and measurement of other compounds in the kernel oil, as well as the chemical analysis of the de-oiled kernel itself. Materials and methods: After picking, jujube fruit was transferred to the laboratory and the oil of the ground kernels was extracted by Soxhlet method. The composition of fatty acids was determined by gas chromatography method and the stability of the obtained oil was determined by Rancimet machine. Also, the substances in kernel oil such as phospholipids, iodine index, acid index, peroxide index, non-saponifiable substances, sterols, tocopherols and color of jujube kernel oil were evaluated. Also, chemical analysis including measuring the amount of ash, dry matter, moisture, oil, protein, and crude fiber was performed on the oiled kernel part. Conclusion: The analysis of jujube seed oil by gas chromatography showed that the content of saturated fatty acids is higher than unsaturated fatty acids. So this oil has high saturation. Oxidative stability of oil showed that jujube seed oil has high stability, i.e. 2.38 hours at 110 degrees Celsius. This oil is similar to coconut oil in terms of oxidation quality, it is also suitable for making cosmetics and health products. Due to its short chain fatty acids and fatty acid profile that has high saturation, jujube kernel oil has a very high resistance and does not cause cardiovascular discomfort and does not increase the level of bad fat. The oxidation stability of jujube seed oil is high, the reason for that is the high saturation of the oil, which means very little oxidation has occurred in jujube seed oil because the amount of phospholipid in jujube seed oil is low. So, we can conclude that according to the average amount of tocopherols, i.e. 22.12%, the majority of the components of this oil are tocopherols, which give more yellowness to the oil, so the color of jujube kernel oil is yellow. This oil is not suitable for frying, but it is very suitable for baking cakes and pastries because the oil has a high melting point and gives a smooth texture to the pastry dough. And finally, due to the fact that the jujube fruit has very useful medicinal and edible properties, its meat can be marketed industrially.

Key words: oxidation stability, fatty acid composition, jujube kernel oil, oil, kernel, jujube.

-1 Background of the research:

Doubt, resorting to medicinal fruits and plants has been the oldest human approach to treat diseases, and during the development of all human civilizations, there has always been a close and close relationship between humans and plants, however, most of the fruit and plant species have not been investigated and remain unknown, and there is still a lot of time left to discover new and valuable plant resources, in this way, plants and fruits can be considered as a source of potentially useful chemicals, only a part of which has been exploited. These potential chemical substances can be used not only as drugs, but also as a unique model as a starting point for making pharmaceutical analogs, and also as an interesting tool to understand biological phenomena more and better. (Skaltsa[1], Digrak[2] et al. 1999, 2001)

Medicinal plants and fruits have a special value and position in providing health and safety of communities both in terms of treatment and prevention. In this century, extensive research has been done on medicinal fruits and plants, and drugs with effective natural compounds have opened new horizons for the community of doctors and research pharmacists around the world.. So that currently about one-third of the drugs used in human societies are drugs of natural and herbal origin, and the pharmaceutical industries of the world are trying to make the chemical manufacturing of items related to two-thirds of the rest of the drugs gradually obsolete and rely on plant sources. Therefore, the pharmaceutical industries and research groups of many countries have focused their attention on the cultivation and production of medicinal plants. (Omid Begi, 2004)

Also, due to the increase in consumer awareness of the undesirable side effects of synthetic drugs and the tendency of humans to use natural products as much as possible in order to maintain their health, as well as modern pharmaceutical problems such as high costs, the use of non-renewable resources such as fossil resources that pollute the environment by the pharmaceutical industry, and the inability of humans to make some medicinal compounds, the use of medicinal plants in the production of drugs and their replacement with chemical compounds became a trend. to show that this is clearly visible in European countries. (Sadraei Manjini, 1382)

In addition to these recommendations of the World Health Organization [3] (WHO) in the use of natural products, in turn, it has caused the production and trade of such products to enjoy a significant boom in the world. Now, different countries are trying to take a significant share of this growing market (Heinberg [4] et al., 2006). )

In addition to medicinal properties, many of these plants are also used as preservatives, preservatives and flavors in the food industry. Due to the presence of essential oils, many of these flavoring plants have a very important source of phenolic compounds that show good antibacterial activity. With a brief look at the culture of using herbal medicines in Iran, the precious heritage of identifying and using these plants in Iran's rich traditional medicine can be seen. On the other hand, the vast plateau of Iran has different climatic conditions in its different parts, and for this reason, the abundance and diversity of different species of these plants in the plains and mountains of Iran reaches more than 7,500 plant species (about ten times the number of species in any European country), and a significant part of them contain valuable metabolic reserves, hence the Iranian flora is considered one of the world's medicinal sources (Omid Beigi, 1383)

Plant oils and extracts and the compounds in them have known antibacterial effects and can be used as food preservatives. (Mehdi Alipour et al., 1388)

The acceptance of this issue is on the one hand due to the new approach of the general public and on the other hand the recommendation of competent international and national organizations in the matter of food hygiene to use different natural preservatives instead of chemicals. In general, vegetable oils and extracts have medicinal and flavoring uses in food (Ankri [5] et al. 1999)

Diseases resulting from the consumption of food contaminated with pathogenic bacteria are of great importance in public health and annually impose a lot of financial and human losses on societies (Sharon[6], Brownella et al. 2001)