scholarly journals Effects of the contents of impurities and seed hulls on the quality of cold-pressed sunflower oil

2012 ◽  
Vol 30 (No. 4) ◽  
pp. 343-350 ◽  
Author(s):  
E. Dimić ◽  
T. Premović ◽  
A. Takači

The effects of different contents of impurities and seed hulls in the raw material on the sensory characteristics, chemical quality, and oxidative stability of sunflower oil prepared by the procedure of cold pressing on a screw press were investigated. It was found that the presence of impurities (up to 10%) and hulls (up to 32%) had an adverse effect on the sensory and chemical characteristics of the oil. The adverse influence on the oils colour was also evidenced from the results of measuring their transparency, which ranged from 14.75% to 43.60%. The presence of impurities and seed hulls caused also a decrease in the oxidative stability of oils, as the values of the induction period ranged from 3.63 h to 4.63 h, while the Totox values were in the range from 2.25 to 5.87.  

2013 ◽  
Vol 8 (1) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Bertrand Matthäus

Argan oil belongs to the high-price vegetable oils on the market. Therefore, consumers have the right to purchase a high-quality product. The quality of edible vegetable oils is defined in food standards in which sensory quality is the most important feature. Additional parameters are defined to assess the identity of oils or to evaluate their oxidative state. The sensory quality of cold pressed argan oil is altered if the production has not been performed with reasonable care regarding raw material and extraction. Only oil from roasted seeds extracted by a screw-press had a sufficient sensory quality over a period of 20 weeks without unacceptable sensory attributes. Under accelerated storage conditions oil from roasted seeds extracted by a screw-press remained below the limits given by the Codex Alimentarius or the German guideline for Edible Fats and Oils for peroxide and totox value. Oil from unroasted seeds or oil from goat- digested roasted seeds and extracted by a screw-press, as well as oil from roasted seeds traditionally extracted, exceeded these limits. Initial oxidative stability of oil from unroasted seeds was significantly lower than that of the other oils. After 35 days under accelerated storage, oil from roasted seeds obtained using a screw-press showed the highest oxidative stability. Moreover, tocopherol and phytosterol compositions are useful features of argan oil.


2010 ◽  
pp. 69-76 ◽  
Author(s):  
Tamara Premovic ◽  
Etelka Dimic ◽  
Aleksandar Takaci ◽  
Ranko Romanic

This paper analyzes influence of different percentage of impurities and hull in the material for pressing on sensory quality (appearance, smell, taste, aroma and colour) of edible nonrefined sunflower oil. It has been concluded that simultaneous presence of impurities and hull in the starting material, especially presence of bigger quantities of impurities, has a rather negative effect on sensory quality of sunflower oil, made by cold pressing on a screw press. Apart from sensory analysis, the effect of impurities and hull on oil colour has also been identified by transparency determining, i.e. content of total pigments - carotenoids and chlorophyll. It has been concluded that presence of bigger quantities of impurities and hull cause the increase of content of both carotenoids and chlorophyll, and at the same time, decrease of transparency value in cold-pressed sunflower oil.


2014 ◽  
pp. 67-77 ◽  
Author(s):  
Tamara Premovic ◽  
Sanja Dimic ◽  
Olga Radocaj ◽  
Etelka Dimic

The objective of this study was to investigate the impact of seed storage time on the quality of cold-pressed sunflower oil. The quality and oxidative stability of oil was determined in samples of domestic varieties of sunflower hybrid, linoleic type seeds, obtained from fresh seeds and from seeds stored in silo cell for 6 and 12 months at temperature below 30oC and in good ventilation conditions. It was found that the longer storage time of seeds had a negative impact on many quality aspects of the oil, such as flavor, odor and aroma, primarily on the sensory profile. Chemical characteristics and oxidative stability of oil were also influenced by the storage time, which was confirmed by increased values of the acid value (AV) and peroxide value (PV) of the oil samples. Fresh seed oil had an AV of 0.49?0.01 mgKOH/g, while oils that were obtained from one-year old seeds had an AV of 1.95?0.02 mgKOH/g. Content of the primary oxidation products in the oil obtained by cold-pressing of the fresh seeds was 1.73?0.02 mmol/kg (measured as PV), and 2.22?0.07 mmol/kg in that from the seeds stored for 12 months. The anisidine value for the oil obtained from the seeds stored for 12 months was 0.86?0.04 (100A1% 350nm).


2020 ◽  
Vol 12 (2) ◽  
pp. 147-154
Author(s):  
Ferymon Mahulette ◽  
Dea Indriani Astuti

Ambonese arrack is one of the traditional fermented beverage product in Maluku, Indonesia. The microbiological research of this beverage that is processed using coconut sap as raw material has never been done before. The research aimed to analyze the microbial succession and chemical characteristics during fermentation of Ambonese arrack. The sample of coconut sap was taken from traditional producer in Mahia village, Ambon. The dominant microbes in the fermentation of Ambonese arrack were Pichia polymorpha and Kloeckera javanica. The highest numbers of these two microbes was obtained after 15 hours fermentation (9.6 log Cfu/mL and 9.9 Cfu/mL, respectively). The sugar content decreased from 593.3 mg/L to 474.3 mg/L, whereas ethanol content increased from 0.0018 g/L to 0.0100 g/L. The pH value decreased from 4.70 to 3.10. The research has isolated indigenous microbes in Ambonese arrack fermentation which was considered as novelty. The bacteria that play a role in fermentation can be used as a starter in the fermentation of various beverage products, especially Ambonese arrack. The results of this research can improve the quality of this fermentation product in the future.


Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 62 ◽  
Author(s):  
Hui Hu ◽  
Hongzhi Liu ◽  
Aimin Shi ◽  
Li Liu ◽  
Marie Fauconnier ◽  
...  

The purpose of the present study is to investigate the changes in extraction yield, physicochemical properties, micronutrients content, oxidative stability and flavor quality of cold pressed peanut oil extracted from microwave (MW) treated seeds (0, 1, 2, 3, 4, 5 min, 700 W). The acid value and peroxide value of extracted oil from MW-treated peanuts were slightly increased but far below the limit in the Codex standard. Compared with the untreated sample, a significant (p < 0.05) increase in extraction yield (by 33.75%), free phytosterols content (by 32.83%), free tocopherols content (by 51.36%) and induction period (by 168.93%) of oil extracted from 5 min MW-treated peanut were observed. MW pretreatment formed pyrazines which contribute to improving the nutty and roasty flavor of oil. In conclusion, MW pretreatment is a feasible method to improve the oil extraction yield and obtain the cold pressed peanut oil with longer shelf life and better flavor.


2017 ◽  
Vol 71 (2) ◽  
pp. 175-182
Author(s):  
Ranko Romanic ◽  
Snezana Kravic

In this paper the oxidative stability of cold pressed sunflower oil of high-oleic type was investigated, using Schaal?Oven test at elevated temperature (63?2?C). At the same time samples of linoleic type oils, cold pressed and refined, were tested. The extent of oxidative changes was analyzed regarding the content of primary and secondary oxidation products during the period of 14 days. To especially expressed increase in oxidative values, with very high values of the coefficient of determination occurred in samples of linoleic type of oils, cold pressed and refined, whereas these changes were much less observed in the sample of cold pressed sunflower oil of high-oleic type (R2 ? 0.99). The cold pressed oils of high-oleic and linoleic type, as well of refined sunflower oil of linoleic type were measured and the content of conjugated dienes and conjugated trienes. In the period of 14 days, the lowest increase in oxidative value and the lowest degree of conjugation into the conjugated diene and triene were determined in cold pressed sunflower oil of high-oleic type, indicating a significantly better oxidative stability of this type of oil compared to linoleic types.


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