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The major aim of the current study was to assess thermal stability of red pigments produced by Monascus purpureus ATCC 16362/PTCC 5303 in submerged fermentation. Natural pigments were produced by Monascus purpureus using stirred tank bioreactor. Stability of Monascus purpureus pigments was assessed under various temperature (50.2–97.8°C), salt (0%–2.5%), and pH (4.3–7.7) values. Thermal degradation constant and half‐life value of the red Monascus purpureus pigments were analyzed using response surface methodology followed by a first‐order kinetic reaction. Results of this study showed that pH, temperature, and salt content could affect red color stability of Monascus purpureus. The pigment showed various stabilities in various thermal conditions (temperature, salt, and pH). At high temperatures, degradation constant of the red pigments increased with decreasing pH, revealing that the Monascus red pigment was destroyed at lower pH values and salt could affect stability of the red pigments at lower temperatures.

In this study, potatoes and onions were fried in sesame oil, canola oil and commercial frying oil at 180 °C for 8 and 4 minutes respectively. The process was performed at three steps. Fried potatoes and onions were evaluated by the measurements of parameters such as fatty acid, tochopherols. The results showed that in terms of changes in fatty acid profile in fried samples, the linolenic acid content in sesame and canola has been decreasing. The highest levels of tocopherol were found in fried samples of sesame oil. Finally, it can be concluded that sesame oil has been shown to be better in terms of resistance to other oils studied in this study.

Sheep and cow butter oils have high consumption and trade rate in the market, but standards regarding type differentiation are lacking. Therefore, the objective of this study was to assess the distinction of the main and molecular components of sheep and cow butter oils. Sanjabi sheep and Holstein cow butters were produced from milk collected in two seasons of summer and autumn via the conventional local method. The main components including fatty acids, triacylglycerols, sterol composition, and PCR test for the evaluation of molecular components were determined in butter oil samples. The most significant differences in fatty acids were for C10:0 and C16:0, and regarding TAGs were for C40, C42, C48, and C50 in sheep butter oils of the two seasons. The sterol composition in cow and sheep butter oils was similar but had differences in the two seasons. PCR tests also showed that cow and sheep butter oils differ in their molecular components. It can be concluded that it is possible to differentiate these two oils using triacylglycerols, fatty acids, and molecular evaluation.

The kernel of cherry, which is obtained from the waste of cherry fruit processing, is classified among non-consumable wastes. In the present study, kernel oil of sour cherry (Cerasus vulgaris Miller) was extracted using cold pressing method and its chemical composition and antibacterial properties against Gram-positive (i.e. Staphylococcus aureus, and Listeria monocytogenes), as well as Gram-negative bacteria (i.e. Escherichia coli and Salmonella typhimurium) were evaluated using disc diffusion and agar well diffusion methods at concentrations of 10 μg/mL, 100 μg/mL, 300 μg/mL, 500 μg/mL, and 800 μg/mL for 24 h and 48 h. The results showed kernel oil of Prunus cerasus L. was rich in polyphenols, flavonoid, anthocyanin, and tocopherol. The kernel oil of Prunus cerasus L. inhibited the growth of all microbial species tested especially Gram-positive strains. The most sensitive microorganism (lowest MIC) among the studied microorganisms was Listeria monocytogenes (MIC: 100 mg/mL). Moreover, Listeria monocytogenes had the largest growth inhibition zone. With increasing oil concentration, the growth inhibition zone increased. Evaluation of the antimicrobial effect, based on the study time (24 h and 48 h), didn’t reveal any significantly difference (p

Perilla oil is one of the best sources of plant-based omega-3 fatty acids while its low oxidative stability triggers deteriorative changes of flavour and thereby it’s reduced domestic usage. The present study was aimed at the formation of one-layered and double-layered nanoliposomes for encapsulating perilla seed oil using chitosan, poly-L-lysine, sodium alginate and genipin. Moreover, physical and oxidative stability of developed nanoliposomes and their in vitro release behaviour were investigated. Formation of coated nanoliposomes was confirmed by FT-IR and TEM analysis, where they showed a satisfactory range of size (200–502 nm) and encapsulation efficiency (82–91%). Indeed, chitosan as primary coating and genipin as a GRAS cross-linker could improve physical and oxidative stability of the developed nanoliposomes and all coated nanoliposomes could benefit stability under gastric and intestinal conditions.

In this article, quantitative analysis of bioactive compounds present in Iranian royal jelly consisted of 10-HDA, acetylcholine, total proteins, soluble proteins including albumin, beta-glubolin, g...

The level of aflatoxin B1 (AFB1) in dairy cow feed ingredients and Total Mixed Rations (TMRs) procured at two farms for low- and high-yielding dairy cows were surveyed. Raw milk from the two groups of cows at each farm was sampled 24 h after feeding the cows with examined feedstuffs during both the rainy and the non-rainy season. The aflatoxin M1 (AFM1) level in the raw milk samples was measured 12-24 h later. The levels of AFB1 in feed and AFM1 in milk were determined by validated enzyme linked immunosorbent assay (ELISA). The influence of farm management and type of feeding system on aflatoxin occurrence were considered. AFB1 and AFM1 were detected in 100% of feed and milk samples, respectively. The average level of AFB1 in the feed ingredients and TMRs were in the range of 1.6-104.7 µg/kg and 11.0-56.0 µg/kg, respectively. The average level of AFM1 in milk samples was 77.0 ng/L. The average concentrations of AFB1 in feeds and AFM1 in milk procured in the rainy season were significantly greater than those procured in the non-rainy season (p1 content. Furthermore, the AFM1 in 75% of milk samples obtained from high-yielding dairy cows and 25% of milk samples obtained from low-yielding dairy cows indicated AFM1 level higher than the maximum allowable Europe Commission limit of 50 ng/L. The results also showed that the occurrence of AFB1 in feed varied with farm feed management. The extent of translocation to AFMI in milk samples was dependent on type of cow, whether low- or high- milk yielding. This study suggests regular risk analysis and using good farm management practices are important to control aflatoxin contamination in feed and milk. Keywords: Aflatoxin B1, Aflatoxin M1, Dairy cows, Feed, Milk yield.

This study aims to extract oil from fresh sour cherry kernel (Cerasus vulgaris Miller) using the cold press method. The oil content and moisture were obtained as 31.89% and 4%, respectively. The organoleptic assessment of the oil was acceptable and the free fatty acid value was obtained as 1.36 (mg KOH/g oil). In addition, peroxide value and anisidine index of sour cherry kernel oil were obtained as 0.99 meqO2/kg oil and 0.15, respectively. The predominant fatty acids were linoleic acid (42.34%), oleic acid (35.45%), α-eleostearic acid (9.34%), and palmitic acid (6.54%), respectively. The kernel oil contained nine major triacylglycerols consisting of OLL (20.44%), OOL (16.99%), LLL (8.20%), LLEl (7.28%), PLO (7.24%), OElO (5.03%), OOO (4.70%), ElLO (4.54%), PLL (4.35%), and POO (3%), respectively. The most abundant sterol compounds were β-sitosterol (83.55%), ∆5-avenasterol (6.8%), sitostanol (4.8%), campesterol (3.5%), and stigmasterol (0.53%), respectively. Also, antioxidant activity, total phenol content (TPC), total anthocyanin content (TAC), total flavonoid content (TFC), total tannin content (TTC), and total tocopherol content were obtained as 73.22%, 33.44 mg GA/g dry matter, 177.84 mg/L, 46.37 mg/g dry matter, and 1.21 mg GA/g dry matter, 832.5 mg/kg oil, respectively. The amount of amygdalin in the oil sample was not detectable.

Bleaching is an important part of the oil refining process, in which pigments, impurities, traces of metals, and oxidative-molecular components of oils are removed. In this regard, the optimization of bleaching conditions can be effective to increase oil quality. In this study, de-gummed and neutralized sunflower oil was bleached at 80, 90, 100, 110, and 120 °C for 15, 25, 35, 45, and 55 min by acid-activated bleaching clay with the concentrations of 0.4, 0.6, 0.8, 1, and 1.2% under laboratory conditions. At that point, peroxide, anisidine, plus Totox values, free fatty acid content, Rancimat, and specific UV absorption at 232 and 270 nm were analyzed via the RSM method. The model optimization using the RSM method revealed that the optimal conditions were 37.31 min, temperature 92.7 °C, and clay concentration 1.18%; this circumstance can meet 86.7% of the expectations as could be met for reducing the factors effective for oxidization during bleaching.

In the present study, green tea extract was encapsulated in liposomes prepared by Mozafari method (without any organic solvents) and characterized for its physicochemical properties e.g. encapsulation efficiency, particle size and z- potential. The obtained results for encapsulation efficiency, particles size and z- potential were 51.34, 419 nm and -57 mV, respectively. Total polyphenol content of green tea was obtained 164.2 mg gallic acid /g extract. Free radical scavenging activities of free and liposomal extract, with using DPPH method were measured 90.6% and 93.37% respectively. Antioxidant activity of ethanolic extract of green tea in free and liposomal form were measured at concentration of 200, 600 and 1000 mg/L on the oxidative stability of canola oil during 60°C temperature for 0, 4, 8, 12, 16, 20, 24, 28 and 32 days. The results compared with synthetic antioxidant butylated hydroxytoluene at 200 mg/L. To evaluate antioxidant activity on canola oil stability, peroxide value, Thiobarbitoric acid, anisidine value, TOTOX and rancimat test measured. Results showed that liposomal green tea extract acted more effective than free extracts. Also, 600 mg/L concentration of green tea extract showed significant antioxidant activity in compare to others. The increasing storage time and different concentrations of ethanolic green tea extracts had significant effects on canola oil stability (P≤0.05). The obtained results showed green tea extract could act as an effective antioxidant. Green tea extract in free and liposomal form at 600 mg/L concentration resulted stronger function than butylated hydroxytoluene synthetic antioxidant.

The study of anthocyanin and phenolic acids has always received much attention due to their extensive range of colors and potential beneficial health effects. In this study extraction of anthocyanins from barberry, eggplant peel and red cabbage was investigated by using different organic solvents. Soluble solid content, antioxidant capacity, total monomeric anthocyanins and total phenolic content were determined and then degradation kinetics of anthocyanin in different solution during freezing process was assayed. In order to examine the effect of different acids on the degree of extraction of anthocyanin and total phenol, varied concentration of hydrochloric, citric and acetic acids were dissolved in a mixture of water and ethanol to prepare acidified aqueous solution. Results indicated that citric acid solution is one of the best solvents for phenolic and anthocyanin extraction which showed the best scavenging activity of DPPH radical. Results from degradation kinetics of total monomeric anthocyanins revealed that stability of anthocyanins in the solution depended on temperature and other ingredients which are present in the medium. Moreover, the present data confirmed that barberry and red cabbage acidified extracts could be one of the more stable natural food colorants based on anthocyanins.

The oil yield, fatty acid (FA) composition, physicochemical, quality characteristics and thermal properties were studied in flax, perilla, and basil seed oils cultivated in Iran. Also the similarities and differences among these seed oils were investigated using principal component analysis (PCA). The results indicated that perilla seed oil contained the highest lipid content followed by flax and basil seed oils. The n-6/n-3 FA ratios of these oils had a range of 0.190–0.320, which was notably lower than those of most vegetable oils. Trilinolenin as the predominant triacylglycerol in the studied flax, perilla, and basil seed oils was found at 21.3, 32.0, and 27.5%, respectively. The bioactive compounds, namely tocols, phytosterols, and total phenolics, present in basil and perilla oils were higher than those of flax seed oil. The results of differential scanning calorimeter indicated that the thermal properties of these seed oils were varied, with lower melting and crystallization peak temperature for perilla and basil seed oils. The results of PCA showed that these seed oils could be distinguished using some components however, C14:0, C16:0, C18:3, UFA and ECN 42 could not be used to discriminate among these seed oils. The results were suggestive of the proper nutritional qualities of the studied oils and their possibly being the potential sources of FAs for enriching the diets with α-linolenic acid and other functional compounds. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13197-019-04158-x) contains supplementary material, which is available to authorized users.

The pollution of the environment by potentially toxic elements (PTEs) is one of the most important raised concerns. Therefore, the current investigation was devoted to measuring the concentration of lead (Pb), cadmium (Cd), elemental mercury (Hg), nickel (Ni), iron (Fe), zinc (Zn), and copper (Cu) in muscle tissue of farmed rainbow trout (n = 30) as well as their feed (n = 15) and water (n = 15) samples collected from farms (Hamadan Province, Iran) by the aid of an inductively coupled plasma atomic emission spectrometer (ICP-OES). Also, the associated risk for human and biomagnification factor (BMF) and bioconcentration factor (BCF) for PTEs in the fish muscle through feed and water were calculated. The mean concentration of Pb, Cd, Hg, Ni, Fe, Zn, and Cu in rainbow trout muscle was reported as 0.056 ± 0.040 μg g-1 wet weight

Egg shell that accounts about 11% of egg weight is one of the industrial wastes that in this research has been used for soybean oil bleaching. The effects of using 1% and 2% of five different types of adsorbents; egg shell powder, egg shell ash, acid activated egg shell powder, acid activated egg shell ash and commercial bleaching earth have been investigated on the bleaching of neutralized soybean oil. The peroxide value, free fatty acid, chlorophyll, carotenoids, metals (copper and iron) and oil retention were determined. Egg shell structure was investigated. According to the results, the bulk of the egg shell consists of calcium and some other compounds such as magnesium, iron and manganese while silicate is the main composition of commercial bleaching earths. The results indicated that soybean oil bleaching with 2% egg shell powder reduced carotenoids and chlorophyll contents up to 82.56% and 46.33%, respectively. Also using of adsorbents based on egg shell reduced significantly (p

This research reports on the studied effect of the intensity of ultrasound (24 kHz) on the quality characteristics of olive oil, sesame oil, sunflower seed oil, and tallow olein. These characteristics (free acidity, peroxide value, conjugated dienes concentration, viscosity, iodine value, turbidity, color values, and melting behavior) were determined in oil samples before and after ultrasonic treatment. Changes in the oxidation parameters showed that the high-intensity ultrasound treatment accelerated the deterioration of oils. In most cases, extra-virgin sesame oil was most resistant to deterioration from sonicating treatments. The decreases in β-carotene content and Hunter values revealed that ultrasound might have good potential for bleaching oils at an appropriate intensity and frequency. The differential scanning calorimeter thermograms, viscosity, and turbidity results indicated that ultrasound probably accelerates the polymerization of the oils. The present study has confirmed that some changes in the physicochemical parameters or structures of oil components had occurred. These changes depended on the sources and initial conditions of the oils as well as the intensity of the applied ultrasound.

Twenty seven Iranian olive oil samples were collected from different provinces to evaluate fatty acids and sterol compositions. The samples were collected from different geographical locations that varied in altitude, temperature, humidity and rain fall. The sample collected from the northern part of Iran by the Caspian Sea had higher oleic acid [G2 sample (75.98%)] and lower linoleic acid [Go5 sample (6.5%)] and palmitic acid [G2 sample (10.78%)] concentrations than samples from the southern part of the country such as F1 whose contents of C16:0, C18:1 and C18:2 were 15.27, 62.73 and 16.09%, respectively, in the southern part, the climate is dry and the temperature variation is wider and the elevation is 1,488 m. The results indicated that oleic acid was the predominant fatty acid with 62.7% for F1 sample in the warmer climate at the south of Iran to 76.0% for G2 sample in the cooler climate in the north of Iran. According to the results, the highest content of β-sitosterol was 87% related to samples G9 and Z3 from the north of Iran and the lowest content was 69.95% related to sample F1–24 from the south of Iran. Clustering techniques such as principal component analysis and hierarchical cluster analysis were carried out on olive composition data to show similarities and discrimination between samples as a function of the cultivation zone. The two methods applied clearly showed the effect of growing regions on the distribution of the olive oil samples in the high dimensional space created by fatty acid and sterol compositions.

Deep fat frying is a method of food preparation which has been popular for quite a number of years. During deep frying, the quality of oil and the finished product decreases as the result of heat treatment of the oil exposed to air at high temperature. Application of heat by microwave as an alternative to the conventional method of frying has become popular in recent years. In this research, the effects of microwave frying on the changes in the quality indices of used oil have been investigated. To achieve this, potato slices were fried in both frying and sunflower oils by application of medium power microwave (550 W) for 20 min, three times a day, for five consecutive days, and oils were sampled for analysis. The results obtained from the chemical tests demonstrated that used frying oil had lower polar compounds, a higher induction period, and more saturated fatty acids than sunflower oil. The interesting point observed was that peroxides formed as the result of oxidation chain reactions were not broken down and were built up due to the lower temperature and shorter period of frying. Therefore microwave frying might be considered as a suitable alternative to the conventional frying due to less degradation of the oil and consequently a lower production of artifacts.

For evaluation of the authenticity of Iranian olive oil, samples from many Iranian olive oil producers especially north of Iran in the production year 2007 were collected. The fatty acid and triacylglycerol compositions were measured. The most recent calculation methods including ∆ECN the difference between the actual and theoretical ECN42 (equivalent carbon number), triglyceride content and R of olive oils according to IOOC methods were applied. On the basis of our results, we were able to classify the olive oils into the extra virgin, virgin olive and olive oil categories. The important fatty acids are oleic, palmitic and linoleic acids and their main triacylglycerols are OOO, POO, OOL, PLO, SOS plus POP, and OLL, respectively. On the basis of the triacylglycerol results, experimental ECN48, ECN46, ECN50, ECN44 and ECN42 were obtained. By using the fatty acids results and a computer program, the theoretical ECN42 and ECN44 were calculated. Then R values, being the ratio of r ECN42/r ECN44 for authenticity of all olive oils and ∆ECN for determining categories of olive oils, were defined. The results of olive oil samples were in the accepted limits of Codex and IOOC. Finally we suggest that the R and ∆ECN can be used in identification of adulteration of olive oils and also they are useful from the point of view of authenticity and classification.

The aim of this study is to evaluate the chemical compositions (total phenol, fatty acid, sterolic compounds) of Iranian virgin olive oil (Zard, Rowghani, Mari) cultivated in the Gilvan (Zanjan Province) and Fadak (Qom Province) regions. Total phenols were determined using the Folin-Ciocalteu assay. Fatty acid and sterol profiles were also analyzed using gas chromatography. In most cases, significant effects (P < 0.05) of cultivars and locations were detected by the chemical composition of the oil samples. The fatty acid analysis indicated that the Mari variety from Gilvan had high oleic/low linoleic acid content; therefore it is a highly resistant olive oil against oxidation. Furthermore, the high mean values of total sterols were also obtained for the Mari variety. The oil of the Zard variety from Gilvan had the maximum amount of phenols as a positive quality index. Therefore, the Mari variety, especially from Gilvan has been suggested as a superior cultivar compared to the Zard and Rowghani varieties.El objetivo de este estudio fue evaluar la composición química (fenoles totales, ácidos grasos, y esteroles) de aceites de oliva virgen iranies (Zard, Rowghani, Mari) cultivados en las regions de Gilvan (provincia de Zanjan) y Fadak (provincia de Qom). Los fenoles totales se determinaron utilizando el método de Folin-Ciocalteu. Los perfiles de ácidos grasos y de esteroles se determinaron mediante cromatografía de gases. En la mayoría de los casos, existen diferencias significativos de los cultivares y los lugares detectados por la composición química (P < 0,05 ). El análisis de ácidos grasos indicó que la variedad Mari de Gilvan presenta una relación alta oleico/ linoleico; por lo tanto, es un aceite de alta resistencia contra la oxidación. Por otra parte, los valores medios altos de esteroles totales también fueron obtenidos para la variedad Mari. El aceite de la variedad Zard de Gilvan presentó la mayor cantidad de fenoles, considerado este valor como un índice de calidad positivo. La variedad Mari especialmente en Gilvan se sugeriere como un cultivar superior en comparación con las variedades Zard y Rowghani.

The aim of this study was to investigate the influences of different concentrations of yellow powder and paste mustard on viscosity, stability, rancidity and organoleptic properties of mayonnaise sauce. The concentrations of mustard in 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05% and 1%, were used in mayonnaise formulation and the results turned out to signify an increase in viscosity, improvement in the other chemical properties with the increasing of the amounts of powder mustard. The sensory properties evaluation demonstrated undesired changes in color and flavor of mayonnaise (p≤ 0.05).Thus, in the next step a thermal treatment applied on powder mustard during which myrosine enzyme and the effective factor in pungent flavor of mustard were deactivated. The produced material, called paste mustard, and with the concentrations of 0%, 0.75%, 1%, 1.25% and 1.5% were used in the production of mayonnaise samples in fully the same circumstances and the above tests all repeated. The results of physiochemical tests and evaluation of sensory properties in comparison of what was observed showed a remarkable increase in viscosity, stability improvement and reduction of rancidity in samples containing paste mustard. However, the undesired changes in color and flavor of the sauce were removed to some extent and the sensory properties of the samples ameliorated (p≤ 05). The research results concluded that mayonnaise sample containing 1% paste mustard without any synthetic preserver, due to high viscosity, appropriate suspension stability, rancidity reduction rate and concerning the desirability of its organoleptic features recognized as the most appropriate sample.

This study was aimed to bleach olive and sunflower oils by using conventional and ultrasonic methods. The qualitative and quantities characteristics of the bleached oils were compared. The used ultrasonic bath (150 W, 20 kHz) was set at two levels of temperatures (45 and 60C). Series of tests including of chlorophyll and carotenoid, color, peroxide value, acidity measurements and free fatty acid (FFA) determination were carried out. By application of conventional bleaching a considerable reduction in chlorophyll and carotenoid contents of olive and sunflower oils were observed, while better removal of the pigments was obtained after ultrasonic treatment for 20 and 30 min at 45 and 60C without any significant negative effect on the fatty acid composition. It might be concluded that the ultrasonic bleaching process can be considered as an alternative method for conventional bleaching method since it could decline the time and temperature of bleaching process. Practical Applications Technical information related to the possible effects of application of ultrasonic bleaching on some of quality parameters of olive and sunflower oils was provided by current study. Ultrasonic waves could improve the bleaching process without any destructive effect on the fatty acids profiles. The suggested method can be used in oil refining industry as alternative to current conventional producer due to reduction of the time and temperature of bleaching process.

The contagious pathogens causing mastitis were evaluated by multiplex polymerase chain reaction (M-PCR) in 4 quarters of the first, third, and fifth parities in industrial, semi-industrial, and traditional dairy cattle farms in Isfahan province, Iran. Prevalence of sub-clinical mastitis caused by contagious pathogens in industrial, semi-industrial and traditional farms was 13.4, 38.2 and 44.2%, respectively, Staphylococcus aureus (S. aureus) was more prevalent than Streptococcus agalactiae (S. agalactia) in all the dairy farms. However, prevalence of S. agalactiae was more in industrial farms as compared to traditional farms. The mean somatic cell count (SCC) did not differ significantly in different farm types. S. aureus was more prevalent than S. agalactiae in each parity number. Mean SCC between M-PCR- and M-PCR+1 status had no significant difference within the first parity. The mean SCC differed significantly with increasing parity number. In M-PCR-status parity number had non-significant effect on mean SCC. Therefore, mean SCC was affected not only by pathogen type and diversity but also by parity number. Key words: Multiplex polymerase chain reaction (M-PCR), somatic cell count,Staphylococcus aureus, Streptococcus agalactiae, contagious pathogen.

The major pathogens causing mastitis were evaluated by multiplex-polymerase chain reaction (M-PCR) with self-designed primers in four quarters of the first, third, and fifth parities in industrial, semi-industrial, and traditional dairy cattle farms in Iran. With the incidence of infection in the quarters by Staphylococcus aureus and Streptococcus agalactiae, the mean log somatic cell count (log SCC) increased from 5.06 to 5.77. The smallest changes occurred with Escherichia coli. Contagious pathogens, when compared with environmental pathogens, were more prevalent and common and created more profound quantitative and qualitative changes in SCC profiles. The second part of the study surveyed the diversity of contaminating pathogens and their effect on quantitative and qualitative profiles of somatic cells. M-PCR was used to determine the absence (M-PCR(-)) and presence of one (M-PCR(+1)), two (M-PCR(+2)), and three (M-PCR(+3)) major pathogens in raw milk samples. Quarter log SCC increased from 5.06 (for M-PCR(-1)) to 5.5 (for M-PCR(+1)), 5.7 (for M-PCR(+2)), and 6 (for M-PCR(+3)). Percent changes in polymorphonuclears (PMNs) were not significant between different quarters and parities but were significant between different farms in terms of pathogen diversity (P0.05). Therefore, by increasing the number of types of major pathogens involved in subclinical mastitis, SCC of udder quarters and the proportion of PMNs significantly increased, whereas the proportion of lymphocytes significantly decreased. This subject is very important in increasing the shelf life of dairy products, because PMNs are introduced to the enzymatic pools.

Preliminary studies by gas chromatography of phytosterols naturally present and added to soya bean oil, indicated that large quantities of these sterols were lost when soya bean oil was exposed to high temperature for a long period. The products which might have been produced as the result of sterol oxidation were not found as members of the nonsaponifiable fraction when this fraction was examined by thin layer and gas chromatography.