Levels Of Rancidity Research Articles

Artificial Intelligence decision-making tools based on comprehensive two-dimensional gas chromatography data: the challenge of quantitative volatilomics in food quality assessment

Effective investigation of food volatilome by comprehensive two-dimensional gas chromatography with parallel detection by mass spectrometry and flame ionization detector (GC×GC–MS/FID) gives access to valuable information related to industrial quality. However, without accurate quantitative data, results transferability over time and across laboratories is prevented. The study applies quantitative volatilomics by multiple headspace solid phase microextraction (MHS-SPME) to a large selection of hazelnut samples (Corylus avellana L. n = 207) representing the top-quality selection of interest for the confectionery industry. By untargeted and targeted fingerprinting, performant classification models validate the role of chemical patterns strongly correlated to quality parameters (i.e., botanical/geographical origin, post-harvest practices, storage time and conditions). By quantification of marker analytes, Artificial Intelligence (AI) tools are derived: the augmented smelling based on sensomics with blueprint related to key-aroma compounds and spoilage odorant; decision-makers for rancidity level and storage quality; origin tracers. By reliable quantification AI can be applied with confidence and could be the driver for industrial strategies.

EVALUATION OF LEVEL OF RANCIDITY OF EDIBLE OIL IN SOME FRIED SNACKS FOOD

This work evaluated the level of rancidity of edible oil in six (6) fried snacks food, namely, beans cake (Akara), groundnut cake (Kuli-kuli), bread buns, fried fish, fried yam chips and fried potatoes chips, purchased from hawkers in Wukari, Taraba State, Nigeria.. The rancidity indicators and their ranges in the samples obtained, include, Acid Value (4.10 – 6.90 mgKOH/g), Free Fatty Acid (2.05 – 3.45 mgKOH/g), Peroxide Value (12 – 46.60 mEq/kg), Moisture Content (4.00 – 44.30 %), Conductivity (0.14 – 1.58 µS/cm) and Viscosity (26.20 – 56.50 mm2/S). The results obtained suggested that the fried snacks foods contain hazardous secondary oxidative products, an implication that the oil in the food sample has become rancid and as such, unsafe for human consumption. The reason given for this is that the oil has been used for frying for too many times instead of the recommended two times. The values obtained in this study far exceeded the stipulated standard acceptable ranges given by WHO, FAO and INSO. It is therefore recommended that the public should be advised and educated that oil that has been used for frying twice should be discarded and not used again. Also, Policy makers and relevant authorities should develop a device for in-situ determination for checking of the quality of oil used for fried snacks food in restaurants without going to the laboratory.

Shelf-life Assessment of Tulsi and Stevia Incorporated Low Sugar Kadaknath Egg Jam

The study was conducted during from September–January, 2020–2021 in the department of Livestock Products Technology, college of veterinary science and animal husbandry, Mhow, Madhya Pradesh, India. The Kadaknath egg jam was developed to increase nutritional content and decrease sugar content, jam with 1% tulsi and stevia was found suitable and most acceptable by sensory panelists. Hence, selected for further storage stability under refrigeration. TBA, FFA value and microbial count of values for control jam were non-significantly (p<0.05) lower as compared to developed tulsi incorporated low sugar kadaknath egg jam throughout the entire storage. A progressive and significant (p<0.05) increased in the TBA and FFA values of control as well as developed tulsi incorporated kadaknath egg jam observed with advancement of storage. The total plate count (TPC) followed a steadily significantly (p<0.05) increasing pattern from 0–15 day in control as well as developed tulsi incorporated low sugar kadaknath egg jam. Psychrotropic counts as well as Yeast and Mold count were not detected on 10 and 15 day of storage respectively in both control and as well as developed tulsi incorporated low sugar kadaknath egg jam. Coliform were not detected during the entire period of storage in both control as well as developed tulsi incorporated low sugar kadaknath egg jam. The observation indicated that microbial count and rancidity level as well as sensory attributes remained well below the permissible level and product was stable up to 15 days of storage under refrigeration (4±1oC).

Integrated Strategy for Informative Profiling and Accurate Quantification of Key-Volatiles in Dried Fruits and Nuts: An Industrial Quality Control Perspective.

Edible nuts and dried fruits, usually traded together in the global market, are one of the cornerstones of the Mediterranean diet representing a source of essential nutrients and bioactives. The food industry has an interest in the selection of high-quality materials for new product development while also matching consumers’ expectations in terms of sensory quality. In this study, walnuts (Juglans regia), almonds (Prunus dulcis), and dried pineapples (Ananas comosus) are selected as food models to develop an integrated analytical strategy for the informative volatile organic compounds (VOCs) quali- and quantitative profiling. The study deals with VOCs monitoring over time (12 months) and in the function of storage conditions (temperature and atmosphere).VOCs are targeted within those: (i) with a role in the product’s aroma blueprint (i.e., key-aromas and potent odorants); (ii) responsible for sensory degradation (i.e., rancidity); and/or (iii) formed by lipid autoxidation process. By accurate quantitative determination of volatile lipid oxidation markers (i.e., hexanal, heptanal, octanal, nonanal, decanal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal) product quality benchmarking is achieved. The combination of detailed VOCs profiling by headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) and accurate quantification of rancidity markers by multiple headspace-SPME (MHS-SPME) answers many different questions about shelf-life (i.e., aroma, storage stability, impact of temperature and storage atmosphere, rancidity level), while providing reliable and robust data for long-range studies and quality controls. The quantification associated with HS-SPME profiling is demonstrated and critically commented on to help the industrial research in a better understanding of the most suitable analytical strategies for supporting primary materials selection and new product development.

Development of Coconut Oil Fermentation MethodS (Cocos Nucifera) Using Rhizopus SP Microbe

Generally, the manufacture of coconut oil still uses high temperatures so it requires a lot of energy or fuel. In this study, the manufacture of coconut oil was developed using the help of Rhizopus sp microbes with the fermentation method. The aim is to save fuel, little residue, low rancidity level, fragrant aroma, free of cholesterol-inducing compounds and to study the effect of microbial weight, fermentation time. The results obtained from the organoleptic test of coconut oil produced a savory taste, fragrant aroma and clear color, in accordance with SNI 7381:2008. The results of the chemical analysis test were pH 4, the free fatty acid value was 0.15%, the peroxide number was 2.97 mekO2/Kg and the saponification number was 246 MgKOH/gr in accordance with SNI 01-2902-1992. Then the microbial test was found Kapang of 1 and Khamar of < 1, in accordance with the standard SNI ISO 2157-1 (BPOM).

Digital Detection of Olive Oil Rancidity Levels and Aroma Profiles Using Near-Infrared Spectroscopy, a Low-Cost Electronic Nose and Machine Learning Modelling

The success of the olive oil industry depends on provenance and quality-trait consistency affecting the consumers' acceptability/preference and purchase intention. Companies rely on laboratories to analyze samples to assess consistency within the production chain, which may be time-consuming, cost-restrictive, and untimely obtaining results, making the process more reactive than predictive. This study proposed implementing digital technologies using near-infrared spectroscopy (NIR) and a novel low-cost e-nose to assess the level of rancidity and aromas in commercial extra-virgin olive oil. Four different olive oils were spiked with three rancidity levels (N = 17). These samples were evaluated using gas-chromatography-mass-spectroscopy, NIR, and an e-nose. Four machine learning models were developed to classify olive oil types and rancidity (Model 1: NIR inputs; Model 2: e-nose inputs) and predict the peak area of 16 aromas (Model 3: NIR; Model 4: e-nose inputs). The results showed high accuracies (Models 1–2: 97% and 87%; Models 3–4: R = 0.96 and 0.93). These digital technologies may change companies from a reactive to a more predictive production of food/beverages to secure product quality and acceptability.

A Quick and Accurate High Performance Liquid Chromatography (HPLC) Method to Determine the Amount of Trimethylamine in Fish Oil Softgels and Multivitamin Softgels Containing Fish Oil

Ocean fish cells contain trimethylamine oxide for osmoregulation. The odorless trimethylamine oxide reduces to trimethylamine by bacterial activity, resulting in a strong fishy odor. Therefore, it is important to find out whether trimethylamine levels in fish oil and multivitamin softgels containing fish oil will affect the quality of the finished products. A derivatization-based, reversed-phase high performance liquid chromatography (HPLC) method was developed using a Lichosphere 100 RP18 column, utilizing acetonitrile and water as the mobile phases. Experimental products were dissolved in ether, followed by a pH jump and buffer exchange, and finally derivatized with 9-fluorenylmethyl chloroformate. Our research has indicated that the level of trimethylamine in the products containing fish oil does not have a correlation with age and rancidity level of the products.

Assessment of Shellac and Lemongrass Oil Blend as Edible Coating to Prolong Shelf Life of Pili Nut (<i>Canarium ovatum</i>)

Shelf life in ground and tree nuts are often assessed based on aesthetic appearance, nut integrity, color and most importantly, taste and edibleness. Nuts with considerable level of rancidity and free fatty acids due to degradation of oils indicate expiration or decay. We prepared a shellac-lemongrass oil blend coating using food-grade ingredients and assessed its potential to extend shelf life of Pili nut (Canarium ovatum) kernels. A glossy, hard but considerably brittle coating for the pili kernels were prepared with varying numbers of layers. On average, the mass of coating added per dip is 0.10 g, and the thickness of 5-layers of coating is 0.3 mm. The obtained reflectance spectra of the coated pili kernels implied the translucent nature of the coating, but becomes opaque as the number of layers are increased. Peroxide value (PV) and free fatty acid value (FFAV), were also measured at 10 days after application of coating. PV was lowest in the nuts with 5 coating layers, while this treatment did not reduce FFAV. These results indicate the effectiveness of our coatings in preventing peroxide production probably by blocking oxygen penetration and ultraviolet exposure, which are important triggers production of peroxide and other free radicals. Further tests and time-series experiments are planned to assess the dynamics of peroxide levels and the overall potential of our coating technology for Pili nut.

Effect of feedstock, impurities, and rancidity on likelihood of spontaneous combustion of oil and biodiesel

Spontaneous combustion of biodiesel has been attributed to the destruction of multiple biodiesel production facilities. This paper investigates common conditions that affect the biodiesel and feedstock oil’s propensity for spontaneous combustion. The objective of this research was to develop a short-term test to determine the likelihood of developing spontaneous combustion in a long term. This study used a completely randomized block design which consisted of four main factors; two feedstocks (linseed oil and waste vegetable oil); two fuel types (raw oil and biodiesel); with or without impurity (sodium methylate, a catalyst used in biodiesel production, was used as an impurity); and two levels of rancidity (fresh and rancid fuel) with a total of 16 combinations. The tests prove all four factors play a significant role in affecting the likelihood of spontaneous combustion. A mathematical quantification was deemed necessary to identify the propensity of spontaneous combustion. A Spontaneous Combustion Severity Index (SCSI), a unitless number, was formulated, based on temperature rise normalized by experiment temperature, which correlates with heat generation patterns inside the reactors from 24-h experiments. Spontaneous combustion of biodiesel was observed under accelerated conditions using a fuel mixture with a SCSI number over 0.015.

Shelf-life Estimation of Instant Pempek Rajungan (Portunus pelagicus) Rancidity with the Arrhenius Acceleration Method

Abstract Rancidity is one of the potential damages to the instant pempek rajungan (Portunus pelagicus) during storage. The purpose of this study was to estimate the shelf life of instant pempek rajungan packed with polypropylene plastic (PP) based on the relationship between storage temperatures and free fatty acids produced. Estimation of shelf life using the acceleration method based on the Arrhenius model. Samples were stored for 30 days at three different temperatures, 25 ± 2 °C, 35 ± 2 °C, and 45 ± 2 °C. The parameter observed during the storage process was an assessment of the rancidity level based on the free fatty acids formed in the sample. Data were analyzed using linear regression and the equation obtained was used to calculate the shelf life of pempek rajungan at room temperature (27 °C). The results showed that the storage time for instant pempek rajungan products at temperatures of 25 ± 2 °C, 35 ± 2 °C, and 45 ± 2 °C could be estimated to be 78, 86, and 70 days respectively with an increase in the number of free fatty acids of 85.2018%, 265.3478%, and 253.1427%. Keywords: Arrhenius, free fatty acid, instant, pempek rajungan, shelf life

Shelf life stability and quality study of texture-modified chicken rendang using xanthan gum as thickener for the consumption of the elderly with dysphagia

A ready-to-eat food called texture-modified chicken rendang (TMCR) was developed for consumption of the elderly with dysphagia in Malaysia. Incorporation of xanthan gum as food thickener in retorted TMCR was evaluated monthly over 6 months’ period for its shelf-life stability and quality. Throughout storage period, both stability and quality of the TMCR samples had reduced significantly, mainly due to lipid and protein oxidation. However, the absence of aerobic and anaerobic bacteria as well as yeast and mould count indicates that TMCR was safe to be consumed. In addition, the TBARs value was found to be within the acceptable limit (under 1.5 mg MDA/kg) indicating low level of rancidity. Overall, the addition of xanthan gum was able to reduce physical and chemical changes imparted from thermal and oxidation processes which affect both quality and stability of the stored samples.

Toxic Compounds Emerged in Brassica Juncea (L) Seed Oil Over Deep Heating are Identified Through Chromatographic Technique and Physio - Chemical Parameters

Oil heating has been degraded by thermal, air and moisture penetration leading to the creation of volatile and non-volatile materials serving as active substrate and increasing temperature and mass transmission levels. In this study, Fresh mustard oil was characterized to assess chemical properties like saponification value (SV), iodine value (IV), peroxide value (PV), p-Anisidine value (p-AV), Totox value (TV), acid value (AV),density and viscosity. The oil was reused (thermal process) for three sets of periods at different heat levels 120, 140, 160, 180 and 200 degrees the impact of the thermal process was examined through physicochemical, nutritional and sensory properties and compared with fresh mustard oil. Chemical compounds were identified for selected oils using GC-MS and FT-IR spectroscopy. The effect of spectra reveals there was a significant change in the thermal refined oils band (180 to 200 ° C) and higher temperature changes the band's exact positions and shifts when the fatty acid ratio has shifted. Similarly, the FT-IR study also found the drastic changes in the functional compounds at 180 to 200°C. The chemical property shows that primary and secondary level of rancidity were confirmed through peroxide value and p-Anisidine value respectively; the consistency and the flow rate was reduced due to the deterioration through rancidity.

Stabilization of rice bran milling fractions using microwave heating and its effect on storage

Rice bran tends to become rancid during storage if it is not stabilized. In commercial rice mills, bran is removed in phases using battery of polishers and different fractions of rice bran are produced. The stabilization reduces peroxidase, lipases, lipoxygenase and auto-oxidation enzymatic activities. The bran fractions were stabilized by continuous microwave heating at different treatment combinations (850, 925 and 1000W; 3, 4.5 and 6min) and stability of bran fractions were analysed in terms of Free Fatty Acid (FFA), Acid value (AV) and Peroxide value (PV) for 90days at the interval of 15days. As power and exposure time increases the FFA, AV and PV are found to be low during storage period. The rancidity level was high in last milling bran fraction and as milling progressed, the rancidity level also increased and it was similar throughout the storage. The bran fractions processed at 925W to 3min found to be the suitable condition for stabilization of rice bran milling fractions.

Lamb burgers made with low and high value cuts: Effect of the spice added and the packaging method on shelf life

ABSTRACTThe use of low-value commercial pieces (breast and neck) of lamb carcass could be an opportunity to made processed-products, increase lamb-meat consumption and revalorize the whole carcass. The synergistic effect of adding spices [rosemary, thyme, sage, garlic or only salt (control group)] along with a packaging system [vacuum (VP), AA: 30%CO2 + 70%O2 or AB: 30%CO2 + 69.3%N2 + 0.7%CO] on microbiological quality, colour (L*, a*, and b*) and lipid oxidation was analysed in burgers made with breast and neck minced meat (1/3; in equal parts) and leg (2/3) during 13 days. The added spice showed a low antimicrobial effect, garlic-burger (in all packaging) presented the highest microbial counts, except for Pseudomonas spp. The combination of rosemary, thyme or sage with VP, AA or AB stabilized the lipid oxidation throughout the study. However, the combination AA-garlic presented the highest discolouration and rancidity level. Packaging with VP or AB of samples-garlic decreased the values of lipid oxidation.

Combined effect of the spice and the packaging method on lamb burgers shelf-life made with high value cuts

ABSTRACTIn order to increase the consumption of lamb meat, new products, such as burgers, were elaborated using leg meat. Since meat products are perishable foods, it is necessary to extend its shelf-life. For this reason, this study examined the combined effect of powdered spices (rosemary, thyme, sage or garlic; a control group non-spiced was used) and a packaging method (vacuum [VP] and two gases mixtures [30% CO2 + 70% O2 (AA); 30% CO2 + 69.3% N2 + 0.7% CO (AB)]) on colour coordinates, microbial counts (total viable count, Pseudomonas spp., Enterobacteriaceae, lactic acid bacteria) and lipid oxidation (LO) over 13 days of storage. Rosemary, thyme and sage stabilized LO values and maintained colour in all packaging tested over time. AA-garlic and AA-control burgers showed the highest discoloration and rancidity levels (p < 0.001). No significant differences were found among batches on microbial quality (except in LAB).

Rapid and non-destructive determination of rancidity levels in butter cookies by multi-spectral imaging.

Rancidity is an important attribute for quality assessment of butter cookies, while traditional methods for rancidity measurement are usually laborious, destructive and prone to operational error. In the present paper, the potential of applying multi-spectral imaging (MSI) technology with 19 wavelengths in the range of 405-970 nm to evaluate the rancidity in butter cookies was investigated. Moisture content, acid value and peroxide value were determined by traditional methods and then related with the spectral information by partial least squares regression (PLSR) and back-propagation artificial neural network (BP-ANN). The optimal models for predicting moisture content, acid value and peroxide value were obtained by PLSR. The correlation coefficient (r) obtained by PLSR models revealed that MSI had a perfect ability to predict moisture content (r = 0.909), acid value (r = 0.944) and peroxide value (r = 0.971). The study demonstrated that the rancidity level of butter cookies can be continuously monitored and evaluated in real-time by the multi-spectral imaging, which is of great significance for developing online food safety monitoring solutions.

HIDROLISIS IKAN BERNILAI EKONOMI RENDAH SECARA ENZIMATIS MENGGUNAKAN PROTEASE BIDURI [Enzymatic Hydrolysis of Low Economic Value Fishes using Biduri’s Protease

Fish protein hydrolyzate is a product obtained from the decomposition of fish proteins into short-chain compounds due to the hydrolysis process either by enzymes, acids, or bases. The purpose of this study was to optimize the production of fish protein hydrolyzate from the low economic value fishes including 'bibisan' (Apogon albimaculosus), 'baji-baji' (Platycephalidae cymbacephalus), and the 'lidah' (Cynoglossus lingua) taken from Talango Island, Madura. The production of fish protein hydrolyzate used enzymatic hydrolysis by biduri’s (Calotropis gigantea) protease. The concentrations of biduri’s protease varied (0, 0.7, 1.4, and 2.1 Unit/g) and at various hydrolysis times (0, 1.5, and 3 h). The experimental design was a Completely Randomized Design with two factors which were carried out in triplicates. The results showed that interactions between the protease concentrations and times significantly affected (at 5% level test) the soluble proteins, maillard products, and the level of rancidity measured as thiobarbituric acid (TBA). The best fish hydrolyzate product based on the soluble protein parameter was resulted from 2.1 Unit/g biduri’s protease and hydrolysis time of 1.5 h. The characteristics of the hydrolyzate were containing 3.51% of soluble proteins, having maillard value of 0.63, and rancidity levels of 12.21 mmol TBA/kg.

Efficacy of Lactoperoxidase System-Whey Protein Coating on Shelf-life Extension of Rainbow Trout Fillets During Cold Storage(4 °C)

The growth and metabolism of gram-negative microorganisms are widely recognized as important reasons for the spoilage of fish and fish product. Based on antimicrobial activity of lactoperoxidase system (LPOS) against gram-negative bacteria, the present study investigated the effect of incorporation of LPOS at concentrations 0 (control), 1.25, 2.5, 5 and 7.5 % (v/v) into whey protein solution as novel antimicrobial coating strategy for rainbow trout (Oncorhynchus mykiss) preservation under refrigeration temperature (4 ± 1 °C) over a 16-day period. During storage of trout fillets, control and 1.25 % LPOS-treated samples reached undesirable levels of rancidity (p < 0.05) at 12th and 16th days, respectively, whereas the higher concentrations showed to be more efficiently stable (p < 0.05) in sensory, chemical (total volatile basic nitrogen (TVB-N) and pH) and microbiological analyses (mesophilic bacteria, psychrotrophic bacteria, Pseudomonas spp. and specific spoilage bacteria). Lipid oxidation in the fillets was not affected significantly by LPOS treatment. The LPOS-whey protein coating also reduced total specific spoilage organisms (Shewanella putrefaciens and Pseudomonas fluorescens) of the fillets more than 1.5 log by the end of storage. The shelf life of samples was extended approximately from 12 days to at least 16 days in the presence of the LPOS. These results indicated the significant antimicrobial activity of the LPOS-whey protein coating solution for refrigerated fish fillets.

Chemical composition and antibacterial activity of Laurus nobilis essential oil towards foodborne pathogens and its application in fresh Tuscan sausage stored at 7 °C

The presence of foodborne pathogens in fresh Tuscan sausage has been reported and these contaminations pose a potential risk to consumers. The objective of the present study was to evaluate the antimicrobial activity of bay leaf essential oil (EO) in vitro and in fresh Tuscan sausage stored at 7 °C for 14 d. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against foodborne pathogens were determined in vitro. The lowest MIC and MBC were found for Escherichia coli (MIC = MBC = 2.5 g/L) and Yersinia enterocolitica (MIC = 1.25 g/L, MBC = 2.5 g/L). Fresh Tuscan sausages were treated with bay leaf EO at 0.05 g/100 g or 0.1 g/100 g and their shelf life was compared to a non-treated control. All groups presented low levels of rancidity (TBARS < 0.5 mg MDA/kg). The EO was able to reduce the population of total coliforms (2.8 log CFU/g) and to extend the product shelf life for two days. Although the presence of the EO affected the sensory characteristics of the sausage, it was considered acceptable by consumers at both concentrations tested. Overall, the results of this study indicate that bay leaf essential oil can be applied in fresh Tuscan sausage to improve its safety and shelf life.

Quality Evaluation of Deep Frozen Scraped Coconut

Fresh scraped coconut is highly susceptible to rancidity and microbial spoilage. Consumer acceptability of frozen scraped coconut in terms of chemical, microbiological and sensorial quality for three months of storage period was aimed in this study. Scraped coconut was taken and steam blanched for 5, 10 and 15 minutes using steamer. Half of blanched coconut was mixed with Vitamin E at 500 ppm. Then it was packed in LLDPE/PET/Al pouches (200 g/pouch) and sealed and stored under frozen condition at -18°C using a domestic freezer for 3 months. Control treatment was carried out by keeping the untreated grated coconut at frozen condition. Total plate count (TPC), free fatty acid (FFA) and peroxide values (PV) were measured in two week intervals for 3 months. Sensory properties of frozen coconut samples were tested in monthly intervals. Results revealed that significantly low FFA values in all the treated samples compared to control. The concentrations were below the detectable levels of rancidity (1% as lauric acid). There was no peroxide value detected throughout the study period in both the control and treated samples. It was evident that an inverse relationship occurred between TPC values and blanching time. No differences were seen in sensory attributes in all frozen coconut and were within acceptable range. Application of steam blanching for 15 minutes with/without addition of vitamin E on fresh scraped coconut has the best advantages to extend the shelf life for minimum of three months to preserve the organoleptic properties at domestic frozen conditions.