scholarly journals Quality Assessment on the Oxidative Stability of Almond Kernels during Extensive Storage Time

2021 ◽  
Vol 22 (2) ◽  
pp. 332-343
Author(s):  
Ahmed Raza Sidhu ◽  
saba Naz ◽  
Sarfaraz Ahmed Mahesar ◽  
Abdul Rauf Khaskheli
Keyword(s):  
Oxidative Stability ◽  
Room Temperature ◽  
Storage Time ◽  
Fourier Transforms ◽  
Spectral Band ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Total Oxidation ◽  
Almond Oil ◽  
Ft Ir

The objective of our study is to monitor the oxidative stability of different cultivars of almonds (Australian, American and Iranian) kernels/oil during the 12th month of storage at room temperature. Several physicochemical parameters free fatty acids (FFA), peroxide value (PV), panisidine value (p-AV), total oxidation value (TOTOX), Fourier transforms infrared spectrophotometer (FT-IR) and Gas chromatography Mass spectrometry (GC-MS) were used to check the oxidative stability of almond kernel. According to the results, effects of room temperature in the early stages of oxidation, primary oxidation products remained stable, whereas secondary oxidation product levels continued to rise in the later stages. In general, FFA increased with increasing storage time, the range was observed (0.21-0.97 %), PV (1.31-16.23 meqO2/kg), p-AV (2.21-19.35), TOTOX (4.83-15.81), respectively. During storage at room temperature for up to 12th months, there was no significant shifting of the spectral band in the FT-IR study. The most bounteous fatty acid in the almond oil range was observed oleic acid C18:0 (71.01-79.56 %) followed by linoleic acid C18:2 (13.13–20.65 %), palmitic acid C16:0 (4.86-5.67 %), stearic acid C18:0 (1.20-3.81 %), and palmitoleic acid C16:1(0.21-0.47 %) in all three samples during storage. These results suggest that almond oil during the 12th month of storage keeps its good chemical properties.

scholarly journals Effect of heating on the oxidative stability of corn oil and soybean oil

2019 ◽  
Vol 70 (2) ◽  
pp. 303 ◽  
Author(s):  
R. Saeed ◽  
S. Naz
Keyword(s):  
Soybean Oil ◽  
Microwave Heating ◽  
Corn Oil ◽  
Acid Value ◽  
Oxidation Products ◽  
Chemical Degradation ◽  
Conventional Heating ◽  
Secondary Oxidation ◽  
Total Oxidation ◽  
Ft Ir

The effects of conventional and microwave heating on the oxidative properties of corn and soybean oil were evaluated. The results showed that acid value, peroxide value, oxidative indices, total oxidation value, and p-anisidine values changed significantly with the rise in temperature (p < 0.05). The peroxide and p-anisidine values for corn oil (PV: 50.670 meqO2/kg, p-AV: 8.248) were greater than soybean oil (PV: 41.694 meqO2/kg, p-AV: 7.566) for conventional heating. The peroxide and p-anisidine values for soybean oil (PV: 6.545 meqO2/kg, p-AV: 76.539) were greater compared to corn oil (PV: 5.074 meqO2/kg, p-AV: 65.360) for microwave heating. The results concluded that microwave heating had a greater impact on the chemical degradation of the fatty acids of the oil. The FT-IR spectra showed peak changes at 3743 cm-1 and 1739 cm-1 and confirmed the rancidity of the oils from microwave heating due to the formation of secondary oxidation products. It was concluded that corn oil showed more oxidative changes compared to soybean oil.

scholarly journals Chemical Variability in the Composition of Zhumeria majdae (Rech. F. & Wendelbo) Essential Oil According to Storage Time and Temperature

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 463
Author(s):  
Akbar Karami ◽  
Fatemeh Tashani ◽  
Aminallah Tahmasebi ◽  
Filippo Maggi
Keyword(s):  
Essential Oil ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Conditions ◽  
Gas Chromatography Mass Spectrometry ◽  
Average Value ◽  
Oil Storage ◽  
Chemical Variability ◽  
Refrigerator Temperature ◽  
Storage Temperatures

Zhumeria majdae (Rech. F. & Wendelbo) is an aromatic herb belonging to the Lamiaceae family, traditionally employed in the Persian medicine for the treatment of a wide number of diseases. In the present study, the chemical composition of Z. majdae essential oil obtained from the plant’s aerial features, and stored at various temperatures (refrigerator temperature 4 °C, freezer temperature −20 °C, and room temperature 20 ± 3 °C) and times (0, 3, 6, and 9 months) was studied. The essential oil was isolated through hydrodistillation, and its composition was evaluated by gas chromatography/mass spectrometry (GC/MS). The results showed that the composition of essential oils changed as a function of the various storage temperatures and times. Linalool (34.85–48.45%), camphor (27.09–39.17%), limonene (1.97–4.88%), and camphene (1.6–4.84%) made up the main volatile compounds which showed differences in their concentrations according to the various storage conditions. Notably, when compared to a non-stored treatment sample (analyzed immediately after essential oil collection), the amount of linalool and camphor increased in all samples stored in all conditions of temperature and time, with the exception of the samples stored for nine months at room temperature. On the other hand, limonene and camphene contents decreased during the storage treatments, showing that the highest content of these compounds occurred in the non-stored treatment. Essential oil storage at the freezer temperature and for three months storage time resulted in the highest average value of the major constituents, highlighting these as the best conditions for obtaining the highest content of the major compounds.

A novel carborane-containing ceramic precursor: Synthesis, characterization, and ceramic conversion mechanism

2018 ◽  
Vol 31 (6) ◽  
pp. 694-706 ◽  
Author(s):  
Dejin Tong ◽  
Haipeng Wang ◽  
Lei Chen ◽  
Lei Wang ◽  
Zhanxiong Li
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Oxidative Stability ◽  
Energy Demand ◽  
Proton Nuclear Magnetic Resonance ◽  
Gas Chromatography Mass Spectrometry ◽  
Linear Polymers ◽  
Model Free ◽  
Ft Ir ◽  
Nuclear Magnetic

Linear carborane-carbosilane-phenylacetylene polymers have been synthesized as precursors for ceramic and characterized by Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), and carbon-nuclear magnetic resonance (13C-NMR). Novel linear polymers have the advantage of being extremely easy to process and convert into ceramics, since they are either viscous liquids or low melting solids at room temperature and are soluble in most organic solvents. Ceramic conversion reaction of the polymers was studied, and the conversion mechanism using thermogravimetric analyzer, FT-IR, and pyrolysis-gas chromatography-mass spectrometry was proposed. During the early heating period in the mechanism, the precursor polymer is cured and oligomer is formed. Then the degradation of oligomer takes place at higher temperatures with the weak bond cleaved and cross-linked simultaneously. Ceramic yield of the polymer after heating up to 1000°C in nitrogen (N2) was 77.6%. The derived ceramics exhibit excellent thermal and thermo-oxidative stability, whose 5% mass loss temperature was identified to be 650°C in N2 and 665°C in air, respectively. Boron appears to be the key element to achieve the outstanding thermo-oxidative stability. The relevant kinetic data were obtained by two kinds of model-free-kinetic algorithms, differential Friedman and integral Kissinger–Akahira–Sunose. These two methods were combined to give the energy profile, which has been identified to be a function of the transformation degree ( α), since the energy demand at each degradation stage is different depending on α.

The Effect of Storage Time on the Composition of the Olive and Sunflower Oils

2015 ◽  
Vol 660 ◽  
pp. 132-137
Author(s):  
Claudia Cobzaru ◽  
Genoveva Bordeianu ◽  
Adriana Marinoiu ◽  
Gabriela Antoaneta Apostolescu ◽  
Cristina Cobzaru ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Olive Oil ◽  
Sunflower Oil ◽  
Room Temperature ◽  
Storage Time ◽  
Oxidative Degradation ◽  
Storage Period ◽  
Anisidine Value ◽  
Sunflower Oils ◽  
Ft Ir

The effect of storage time on the composition of the olive and sunflower oils has been investigated. It were studied parameters like free fatty acids (FFA), anisidine value (AV), iodine value (IV), saponification number (SN) and identification of the molecular structure through FT-IR method. During storage (48 months) an increasing in the values of parameters FFA and AV took place that measures the oxidative degradation of oils. The oxidative stability of olive oil stored at room temperature was less than of sunflower oil. Also, significant differences were found among the olive oil and sunflower oil during storage period.

scholarly journals Effect of seed quality on oxidative stability of cold-pressed sunflower oil

2015 ◽  
Vol 69 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Etelka Dimic ◽  
Tamara Premovic ◽  
Aleksandar Takaci ◽  
Vesna Vujasinovic ◽  
Olgica Radocaj ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Sunflower Oil ◽  
Storage Time ◽  
Seed Quality ◽  
Seed Mass ◽  
Seed Storage ◽  
Conjugated Dienes ◽  
Oxidation Products ◽  
Cold Pressed ◽  
The Impact

The objective of this study was to investigate the impact of the storage time, content of the husk and impurities in the seed mass on the oxidative stability of the cold pressed sunflower oil. The oxidative stability of oil was analyzed by the RSM (Response Surface Methodology), where the response value (output) of the model was the content of oxidation products measured via specific absorbance at 232 nm for conjugated dienes and 270 nm for conjugated trienes. Analyses were performed on the fresh oil samples and oil samples tempered under the Schaal-Oven?s test conditions (96 h at 63?2?C). It was concluded that the seed storage time had significant impact on the primary (A1%232nm) and secondary (A1%270nm) oil oxidation products, both before (b1-p<0,001; b1-p=0,021) and after (b1-p=0,048; b1-p=0,033) the heating of oil. The content of impurities and husks in the seeds used for pressing also had an influence of the conjugated dienes and trienes contents in both, fresh and heated oil samples. However, their impact was not statistically significant. Interaction of seed storage time, the content of impurities and husks also exert some effect on the values of these quality parameters in the fresh oil as well as in the oil after the heat treatment, even though their influence is not significant. The obtained results have shown that the cold pressed sunflower oil had a good oxidative stability at temperatures up to 63?2?C.

scholarly journals Drying and storage of macaúba fruit: chemical and oxidative stability

2020 ◽  
Vol 41 (3) ◽  
pp. 865
Author(s):  
Vanessa Mandú da Silva ◽  
Rita de Cássia Avellaneda Guimarães ◽  
Raquel Pires Campos ◽  
Aurélio Vinicius Borsato ◽  
Priscila Aiko Hiane ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Free Radical ◽  
Oxidative Stability ◽  
Room Temperature ◽  
Storage Time ◽  
Oil Quality ◽  
Titratable Acidity ◽  
Acidity Index ◽  
And Storage

The objective of this study was to evaluate the chemical and oxidative stability of dried macaúba (Acrocomia totai) fruit in different air conditions and stored for up to 120 days. The macaúba fruits were collected, sanitized, dried at the temperatures of 40, 50, 60 and 70 °C and stored in raffia bags at room temperature. Drying at higher temperatures resulted in pulps with a darker and orangish color and pulp oil with lower titratable acidity contents and acidity indices. Throughout storage, there was an increase in the acidity index of pulp oil and a reduction in the ascorbic acid and carotenoid contents in the pulp. Drying and storage reduced the ascorbic acid and carotenoid contents of the pulp. Drying at lower temperatures results in pulps with a higher free-radical sequestering ability. Pulp oil quality was compromised by drying and storage time. Newly harvested macaúba fruits can be dried at 40, 50, 60 or 70 °C and stored for up to 120 days without compromising nut oil quality.

scholarly journals Development of walnut oil and almond oil blends for improvements in nutritional and oxidative stability

2020 ◽  
Vol 71 (4) ◽  
pp. 381
Author(s):  
F. Pan ◽  
X. Wang ◽  
B. Wen ◽  
C. Wang ◽  
Y. Xu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Oxidative Stability ◽  
Oxidation Stability ◽  
Significant Negative Correlation ◽  
Oxidation Products ◽  
Walnut Oil ◽  
Almond Oil ◽  
Accelerated Oxidation ◽  
Oil Blends ◽  
Fatty Acid Compositions

For the increase in oxidative stability and phytonutrient contents of walnut oil (WO), 5, 10, 20 and 30% blends with almond oil (AO) were prepared. The fatty acid compositions and the micronutrients of the oil samples such as tocopherol, phytosterol and squalene were measured by GC-MS and HPLC. It was found that the proportions of PUFAs/SFAs in blended oils with high AO contents were lowered, and the blends contained higher levels of tocopherols, phytosterols and squalene than those of pure WO. The 60 °C oven accelerated oxidation test was used to determine the oxidative stability of the blended oil. The fatty acid composition, micronutrients and oxidation products were determined. The results showed that the oxidation stability of the blended oil increased with an increasing proportion of AO. In addition, a significant negative correlation between micronutrient and oxidation products was observed as the number of days of oxidation increased.

scholarly journals Impact of the seed storage time on the quality of cold-pressed sunflower oil

2014 ◽  
pp. 67-77 ◽  
Author(s):  
Tamara Premovic ◽  
Sanja Dimic ◽  
Olga Radocaj ◽  
Etelka Dimic
Keyword(s):  
Oxidative Stability ◽  
Sunflower Oil ◽  
Storage Time ◽  
Seed Storage ◽  
Oxidation Products ◽  
Sensory Profile ◽  
Quality Aspects ◽  
Cold Pressed ◽  
The Impact

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).

scholarly journals Aktivitas Antioksidan Bubuk Sargassum hystrix Selama Penyimpanan pada Suhu Berbeda

2020 ◽  
Vol 40 (3) ◽  
pp. 175
Author(s):  
Pingkan Mayestika Afgatiani ◽  
Amir Husni ◽  
Siti Ari Budhiyanti
Keyword(s):  
Antioxidant Activity ◽  
Water Content ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Temperature ◽  
Total Phenol ◽  
Gas Chromatography Mass Spectrometry ◽  
Sample Analysis ◽  
Ic50 Value ◽  
Before And After

The aim of this study was to determine the effect of storage temperature on the antioxidant activity of Sargassum hystrix. Samples were collected from Sepanjang Beach Gunung Kidul, Yogyakarta, and dried, pulverized, and then stored for two months at room temperature (17-33 °C), refrigerator (4 °C) and freezer (-18°C). Furthermore, the samples were tested every two weeks to determine their water content, total phenol, DPPH, and FIC. Also, Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed for two months before and after storage. The results showed that the water content increased after treatments, along with storage time which ranges from 8.55 to 14.27 %. Total phenol before storage was 175.73 mg GAE/g extract, and freezing has the highest total phenol levels after storage which was 22.07 mg GAE/g extract. Also, DPPH testing showed S. hystrix has anIC50 value of 0.45 mg/mL, and refrigeration has the lowest IC50 value of 3.18 mg/mL. FIC test showed IC50 value of 1.44 mg/mL, and freezing has the lowest FIC IC50 value of 15.36 mg/mL. In addition, GC-MS sample analysis before storage detected 8 compounds with antioxidant activity of 86.96 %. After two months, they were detected at room temperature, refrigerator, and freezing which are 4, 3, and 8 compounds respectively.

scholarly journals Effect of α-tocopherol, rosemary extract and their combination on lipid and protein oxidation in beef sausages

2021 ◽  
Vol 854 (1) ◽  
pp. 012062
Author(s):  
B Nacak ◽  
H S Kavuşan ◽  
M Serdaroğlu
Keyword(s):  
Oxidative Stability ◽  
Protein Oxidation ◽  
Storage Time ◽  
Meat Products ◽  
Thiobarbituric Acid ◽  
Rosemary Extract ◽  
Thiobarbituric Acid Reactive Substances ◽  
Total Oxidation ◽  
Lipid And Protein Oxidation ◽  
And Storage

Abstract This study focuses on the oxidative changes in lipids and proteins of beef sausages with incorporated a-tocopherol, rosemary extract or their combination during 3 months’ storage at 4°C. For this purpose, sausages were formulated with no antioxidant (Control, C), 200 ppm a-tocopherol (T), 200 ppm rosemary extract (R), and 100 ppm a-tocopherol + 100 ppm rosemary extract (TR). To observe oxidative changes in lipids; peroxide value, thiobarbituric acid reactive substances (TBARS), and total oxidation value (TOTOX), in proteins; sulfhydryl and carbonyl contents were measured. Use of antioxidants and storage time significantly affected oxidative stability of sausages (P<0.05). Antioxidants, individually or in combination, retarded lipid peroxidation and improve the oxidative stability of sausage during storage. The antioxidant combination showed synergistic effect on protein oxidation, as the lowest carbonyl contents were found in TR samples. As a result, a combination of antioxidants with different effect mechanisms could be the better option to prevent oxidative changes in meat products.

Sign in / Sign up

Export Citation Format

Share Document