THE QUALITY OF VEGETABLE OIL FROM THREE VARIETIES OF SUNFLOWER SEEDS (HELIANTHUS ANNUUS)

ABSTRACT

Vegetable oils become susceptible to oxidation during their processing. The appropriate extraction and refining conditions of oil from two experimental cultivars (Madero‐91 and Cianoc‐2) of sunflower seeds and a commercial one (Victoria) as a control, were studied. Isopropyl alcohol was used in the extraction and refining, and compared with hexane. The refining was performed by the miscella method at 40, 50, 60 and 70%. Free fatty acids (FFA) and malonaldehyde analysis of crude oils afforded no significant differences among solvents and sunflower varieties. In refined oils, differences found with the miscella concentration, the malonaldehyde content and FFA content were not significant. Cianoc‐2 was the best source for oil production because of its lower values in FFA and malonaldehyde content.

PRACTICAL APPLICATIONS

The use of hexano in refining vegetable oil in Mexico is common, lack of knowledge about the use of new solvents and their impact on the processing conditions with sunflower seed cultivars is lack. The present work describes at lab scale, the work conditions, advantages and posibilities and limitations of the use on isopropyl alcohol in comparison with hexane and the use of three Mexican cultivar with this approach, with emphasize in oxidation conditions of refined vegetable oil.

     

TOTAL QUALITY INDEXES FOR EXTRA-VIRGIN OLIVE OILS

ABSTRACT

In this article, we propose a new and functional mathematical index, able to describe and compare the nutritional, safety and process quality in extra‐virgin olive oil, introducing a definition of “optimal” oil, through the use of appropriate distances in a N‐dimensional parameter space. Our index does not pretend to be the unique answer to the need of a “quality index,” but it presents a way through which we can establish if an extra‐virgin olive oil can be considered of high, medium or low quality. The main goal of our index is to link oil chemical quality to its commercial price; furthermore, it can be, in perspective, useful to detect the critical points (such as harvest time, drupe storage, processes and finally oil storage) during all the production chain, and to show how to increase nutritional, safety and technological quality.

PRACTICAL APPLICATIONS

The index could be mainly helpful for consumers because the only indication that they can use today, in order to operate a choice, is in general the price of the oil, which is not necessarily related to its quality. In fact, it is possible to relate our index to the oil price. This tool can also be addressed to producers, to help them to detect the critical points along the whole food production chain and eventually operate the needed corrections to obtain a high‐quality extra‐virgin olive oil, as stated in the Discussion.

     

EFFECT OF ROSEMARY ON THE QUALITY CHARACTERISTICS OF WHITE SHRIMP (LITOPENAEUS VANNAMEI)

ABSTRACT

We assessed the influence of rosemary on some of the quality characteristics of Litopenaeus vannamei shrimp stored under freezing temperature for 180 days. Whole shrimp (WS), peeled shrimp (PS) and PS with dehydrated rosemary (RS) were stored at −28.3 ± 3.8C. Physicochemical and sensorial analysis was carried out. After 180 days, RS had lower pH (P = 0.001) and thiobarbituric acid‐reactive substances (TBARS; P = 0.001) values and higher carotenoids (P = 0.003). WS samples were firmer at 180 days (P = 0.001), although rancid taste and smell were perceived with greater intensity (P = 0.001). The color was more intense in RS and PS than in WS (P = 0.030). Rancid taste was detected in RS only at 120 days at significantly lower intensity (P = 0.001) than WS and PS. Our study suggests that dehydrated rosemary can improve the quality of frozen L. vannamei peeled shrimp.

PRACTICAL APPLICATIONS

Farmed shrimp has gained importance in the global market, and the study of their physicochemical and sensory characteristics is therefore essential. Commercially, shrimp is mainly available in the frozen form, and alternatives to extend its quality during storage are of great interest for consumers and suppliers in the food industry. Dehydrated rosemary can be added to frozen shrimp to improve its quality and maintain the nutritional characteristics during storage.

     

SENSORY EVALUATION OF THE TEXTURE OF 49 COMMERCIAL APPLE AND PEAR PUREES

ABSTRACT

The sensory texture of 49 market samples of pear and apple purees were examined by Flash profile and results were treated by Generalized Procustes Analysis. The product set encompassed grocery products, baby foods and drinking snacks. Four main sensory notions were used to describe the texture of this type of products: graininess, viscosity, moisture and grittiness. Pear and apple purees were discriminated by the gritty perception, carried out on the third component. The other three main characteristics were carried out on the first two axes, where six main groups of products were identified. Pear purees were close to baby foods. Thickened baby foods and pear and apple mixtures constituted additional groups. Finally, apple purees were close sensorially, but three groups could be discriminated by grainy and viscous perceptions. The number of products was not an obstacle and the panel managed the task as required.

PRACTICAL APPLICATIONS

Flash profile seems to be a powerful tool to provide a statement of the sensory diversity of a specific market very quickly even when the number of products is quite large.

     

PREVALENCE OF ANTIMICROBIAL RESIDUES IN MILK AND DAIRY PRODUCTS IN THE STATE OF KUWAIT

ABSTRACT

Approximately, 1,000 locally produced and imported milk and dairy product samples were collected at different seasonal periods from different farms and retail outlets in Kuwait, and screened for the presence of four antimicrobial residues (beta‐lactams, tetracyclines sulfonamides and chloramphenicol) using Charm II system. Results indicated that 29.1% of the analyzed local fresh milk samples were above the maximum residue level (MRL) for tested residues with tetracycline as predominant residue. The prevalence of antimicrobial residues in imported pasteurized milk samples (5.4%) was higher than that of local pasteurized milk samples (3.4%). No residues were detected in powdered and condensed milk samples imported from the European Union (EU) countries with the exception of tetracyclines. Results also showed that 9.4% of the analyzed imported cheese samples were above the MRL for tested residues, while tested ice cream samples were negative for antimicrobial residues. The significant presence of antimicrobial residues, particularly chloramphenicol, in raw and pasteurized milk, clearly implies the misuse of antimicrobial drugs in animal farms in Kuwait and neighboring countries, and implies the need for stricter regulations on antimicrobial drug usage in the dairy industry.

PRACTICAL APPLICATIONS

This article addresses the generation of a baseline data on the current presence of four antimicrobial residues in locally produced and imported milk and dairy products in the state of Kuwait. The outcome of this study will provide valuable baseline information for local governmental authorities for effective monitoring for the use and misuse of agricultural antimicrobial drugs. Such data will also be important for other Gulf Cooperation Council countries, because such countries share similar farming practices and import comparable foodstuffs.

     

DETERMINATION OF THE PROTEIN CONTENT IN RICE BY THE DIGITAL CHROMATIC METHOD

ABSTRACT

The feasibility of using digital chroma measurements to determine the protein content in rice was investigated using red, green and blue (RGB) chroma values to reflect color change. The protein content of rice samples ranged from 5 g/100 g to 13 g/100 g. There was a significant negative linear correlation (r < −0.98) between the protein content in rice and the chroma values of relevant protein solutions treated with biuret reagent. Of all the tricolor values, the G value was the optimal parameter to reflect the chroma difference of the protein solutions. It had a higher correlation coefficient (r < −0.99) and was more sensitive to subtle differences in protein content than R or B values. With a similar structure and the same reaction conditions, rice samples with known protein content were found to be more accurate calibrating substances. The results determined by the digital chromatic method are not significantly different from that of the Kjeldahl method. With the advantages of high precision, easy operation and high efficiency, the method is suitable for applications in quality evaluation and supervising practice in the field of rice circulation.

PRACTICAL APPLICATIONS

A new method to determine the protein content of rice was studied by combining digital image analysis technology and a traditional chemical approach. The study forms a part of the technology foundation to develop quality evaluation systems for rice.

     

THE EFFECT OF PROCESSING METHOD ON THE CHARACTERISTICS OF CARROT JUICE

ABSTRACT

The production of carrot juice using different technologies is the main subject of this investigation. Although the production and preservation of the carrot juice technology have not been improved and are not prevalent, an intensive study has been carried out on this subject recently. In this study, the effects on the yield and quality of carrot juice produced with and without total enzymatic liquefaction (Pectinex Ultra SP‐L, Novo Nordisk Ferment, Dittingen, Switzerland) as well as lactofermentation or citric acid addition have been investigated. Generally, enzymatic liquefaction of mash increased the juice yield (89.32 ± 1.17 and 90.43 ± 0.47% for lactofermented and citric‐acid‐added samples, respectively), while the control sample juice yield was found to be 59.90 ± 0.81%. Lactofermented and acid‐added samples demonstrated lower pH value. In enzyme‐treated samples, the total acidity increments were also determined. Accordingly, galacturonic acid formed after enzymatic breakdown of pectin in the raw material increased the total acidity of the samples. Magnesium contents of lactofermented juices were found to be low because lactic acid bacteria require magnesium for their growth. β‐Carotene contents have been found to be higher in both lactofermented and in nonenzyme‐treated samples.

PRACTICAL APPLICATIONS

This article describes the effects of different processing methods on the characteristics of carrot juice. It is difficult to preserve vegetable juices such as carrot juice because of their low acidity. The acidity of carrot juice (pH ～6.2) can be adjusted by the addition of citric acid or the lactofermentation method to pH 4.5. With these processes carrot juice can be preserved by pasteurization as occurs for low pH fruit juices, increasing shelf life. According to the results of this study, increasing the acidity of mash with lactofermentation or citric acid addition also increases the juice yield.

     

THE INFLUENCE OF ADDITION OF DEFATTED BLACKCURRANT SEEDS ON PRO‐HEALTH CONSTITUENTS AND TEXTURE OF CEREAL EXTRUDATES

ABSTRACT

Extrudates used in the study were prepared on the base of cornmeal (100%) – control, which was in 10, 30 and 50% replaced by defatted seeds of blackcurrant, which were a by‐product of supercritical fluid extraction, used for oil production. The aim of the study was to check the influence of the level of defatted blackcurrant seeds, on texture and chemical composition of the obtained extrudates. Special attention was paid to pro‐health constituents, i.e., dietary fiber, polyphenols, flavonoids and anthocyanins. The addition of defatted seeds resulted in an increase of polyphenol content, and antioxidant activity, and the rise in the level of flavonoids and soluble dietary fiber as compared with control. The enrichment of extrudates in pro‐health components, as well as improvement of sensory score, suggests that 10% addition of defatted blackcurrant seeds is a suitable level for preparation of extruded fruit‐cereal snacks.

PRACTICAL APPLICATIONS

The study demonstrates that defatted blackcurrant seeds could be a good, natural source of bioactive components in cereal snacks produced by extrusion. The suggested level of this component, optimal from sensory and dietary point of view, is 10%.

     

ANTIOXIDANT PROPERTIES OF LENTINUS EDODES AND AGARICUS BLAZEI EXTRACTS

ABSTRACT

This work aimed to evaluate the antioxidant activity of Lentinus edodes and Agaricus blazei mushrooms, as well as to measure the content of total phenolic compounds of mushroom extracts and verify the oxidative stability of soybean oil added with mushroom extracts that showed higher antioxidant activity according to the methods of the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^•) free radical scavenging and the β‐carotene/linoleic acid system. According to the DPPH^• method, the maximum antioxidant activity for L. edodes and A. blazei methanol extracts was 92.84 and 95.10%, respectively. For the β‐carotene/linoleic acid system, the highest values of antioxidant activity were 93.06% for L. edodes and 78.96% for A. blazei. The content of total phenolic compounds ranged from 7.21 to 128.44 and 26.67 to 134.67 mg gallic acid equivalent/g for L. edodes and A. blazei, respectively. The oxidative stability values provided by the Rancimat method indicated that the two varieties presented similar induction period of 19.85 h.

PRACTICAL APPLICATIONS

Mushrooms present high content of antioxidant compounds that are capable of reducing the harmful effects of free radicals. Among the antioxidants present in mushrooms, phenolic compounds stand out as phenolic acids, flavonoids and tocopherols. To decrease or prevent lipid oxidation, synthetic antioxidants are used as food additives. Nevertheless, studies have revealed that these compounds are likely to pose risks to human health. The concern regarding the safety of synthetic antioxidants has motivated the search of natural antioxidants that can substitute them totally or partially.

     

QUALITY AND SAFETY CHARACTERISTICS OF MILK SOLD IN THE STATE OF KUWAIT

ABSTRACT

The food chain operational links for locally produced and imported milk were prepared. Quality and safety assessment of milk were also carried out by collecting raw milk samples from the farms, and pasteurized milk from retail and wholesale outlets. Milk samples were analyzed for pH, titratable acidity, clot on boiling, aflatoxin M1, antibiotic residues, and microbiological quality and safety. Results have shown that the mean pH and acidity of raw milk were 6.83 and 0.180%, while the mean pH and acidity values for local and imported pasteurized milk were 6.9 and 0.170%, and 6.8 and 0.150%, respectively. Furthermore, all raw and pasteurized milk samples were negative for the clot on boiling test and were within the allowable limits for aflatoxin M1 and antibiotic residues. However, raw milk samples collected from the local dairy farms were unacceptable because of the high somatic cell count and high Staphylococcus aureus counts.

PRACTICAL APPLICATIONS

Securing an adequate food supply for the nation has always been the fundamental concern of Kuwait's policy makers. Under local Kuwaiti conditions, with high temperatures over most of the year and the high level of imported products with unknown histories, combined with handling by unskilled labors, food losses can be excessive. This situation creates marketing problems for some of the highly perishable foods like milk. The baseline data of milk losses obtained during this study would help to bring about improvements in storage, handling and distribution practices and develop recommendations for private/public agencies to adopt technologies for improving milk losses. Furthermore, since there are no accurate statistics on milk losses in Kuwait, these primary data could be used to determine the economic values of milk losses in Kuwait.

     

THE EFFECT OF pH ON THE EFFICIENCY OF VINIFICATION BY‐PRODUCT EXTRACTS TO INHIBIT LIPID PEROXIDATION IN A LECITHIN LIPOSOME MODEL MATRIX

ABSTRACT

A series of extracts from vinification by‐products, generated under specified, optimal conditions, were tested for their efficiency to inhibit lipid peroxidation in lecithin liposomes at various pH values. Lipid peroxidation was assessed by measuring the kinetics of CDV onset, which over a period of 6 days was found to obey zero‐order kinetics. As positive control samples the synthetic antioxidant, butylated hydroxytoluene and the natural quercetin were also considered. The results obtained showed that the most distinct inhibition as compared with control sample (no antioxidant added) was found upon addition of grape stem extract from the variety Vitis vinifera var. Moschofilero at pH 8, with the kinetics constant (k) being 6.6 × 10⁻² CDV/d. By contrast, seed extract from the same variety at pH 2 was prominently prooxidant, with k = 50.7 × 10⁻² CDV/d. Extracts from both stems and seeds exhibited large variations as a function of pH, with stem extracts being in general more efficient than seed extracts, but no consistent trend in response to pH was observed. This outcome clearly pointed to efficiency dependence upon both the composition of the extracts and pH.

PRACTICAL APPLICATIONS

Because the use of antioxidants in food industry is indispensable, the study of the efficiency of certain widely used plant extracts possessing antioxidant properties becomes imminent. This is because the deployment of natural antioxidants in food matrices has often been accompanied by major discrepancies concerning their efficiency to shield against rancidity. Thus, revealing details on the antioxidant behavior of natural extracts with regard to significant food characteristics, such as pH, is of undisputed importance in utilizing these extracts in a technologically rational way. The results from this study showed that extracts from vinification by‐products, and presumably other extracts from various plant sources, might have variable behavior with regard to inhibiting and/or promoting lipid peroxidation. As this might depend on the pH of the matrix used or other intrinsic factors, the antioxidant potency of a particular extract can be reliably assessed only by case experimentation.

     

EFFECT OF PACKAGING MATERIALS ON THE QUALITY OF IRON-FORTIFIED WHOLEMEAL FLOUR DURING STORAGE

ABSTRACT

The effect of packaging materials on the physicochemical and rheological characteristics of iron‐fortified wholemeal flour (WMF) during storage was determined. WMF was fortified with three fortificants, namely ferrous sulfate (30 ppm), ferrous sulfate + ethylenediamine tetraacetic acid (EDTA) (20 + 20 ppm) and elemental iron (60 ppm). Each flour was also fortified with 1.5 ppm folic acid. Moisture, flour acidity and peroxide value increased during storage, while protein and fat contents decreased. Highest conversion of Fe²⁺ into Fe³⁺was observed in flour fortified with ferrous sulfate (2.72%), followed by that fortified with ferrous sulfate + EDTA (1.49%) and elemental iron (1.06%). Water absorption and dough viscosity of iron‐fortified flours increased during storage. The flour containing ferrous sulfate was most acceptable regarding sensory characteristics, followed by samples containing ferrous sulfate + EDTA. Fortified flours were more stable during storage than unfortified. Addition of EDTA increased the stability of flours and fortificants. The fortified flours stored in polypropylene bags proved more stable than those stored in the tin boxes.

PRACTICAL APPLICATIONS

The main role of packaging is to protect the product during handling, distribution and storage against environmental and mechanical hazards. The success of a fortification program depends on the stability of micronutrients and food to which these are added. Chemical changes during storage badly affect chapatti making and sensory properties. Exposure of the fortificant to any factor including heat, moisture, air or light, and acid or alkaline environments during processing, packaging, distribution, or storage affects its stability. Flour containing elemental iron and ferrous sulfate with EDTA remained stable up to 42 days. The unfortified flour and flour containing ferrous sulfate remained stable for 21 days in tin boxes and 28 days in the polypropylene bags. Wheat flour milling industry would be benefited from this research if government is keen to launch iron fortification program in the country to curb iron deficiency anemia among population.

     

RELATIONSHIP BETWEEN RHEOLOGICAL BEHAVIOR AND BOSTWICK MEASUREMENT DURING MANUFACTURE OF KETCHUP

ABSTRACT

The Bostwick consistometer remains an integral part of assessing the consistency of tomato products. For instance, the consistency of lots of tomato paste are designated at the factory by their Bostwick measurement; tomato ketchup is produced to meet Bostwick ranges given in U.S. Standards for Grades. This work addresses the blending of tomato pastes, at different Bostwick readings, for use in the remanufacture of ketchup. For both blends and ketchup, the Bostwick measurement was correlated to rheological parameters measured by two methods: a single‐point method and rotational viscometry. The correlations between the Bostwick measurement and the viscosity were compared with the theoretical prediction based on gravity current flow. The results illustrate that the relationship between the Bostwick measurement and (K/ρ)^?1/(2n+3) provides a means to predict the Bostwick length from at‐line or in‐line viscosity measurements.

PRACTICAL APPLICATIONS

The results of this work provide a means to predict the Bostwick length from at‐line or in‐line viscosity measurements. Specifically, the quantitative relationships presented in the article allow in‐line process control schemes to improve final product quality.

     

PRODUCTION, QUALITY ASSESSMENT AND ACCEPTABILITY OF AFRICAN YAM BEAN SPHENOSTYLIS STENOSCARPA SAUCE

ABSTRACT

Sauces (15 and 20% brine solution) were made from African yam beans (AYBs) using a combination of solid and liquid state fermentations as practiced in Indonesia. They were analyzed to ascertain their nutritive value, microbiological safety and consumer acceptability. Results showed that the protein, fat, ash and carbohydrate contents were 4.85, 3.82, 11.82 and 16.75%, respectively, for 15% brine solution sauce after spicing and concentration. The total microbial load (bacteria) of the sauces was relatively low (20.0 and 18.0 cfu/g × 10⁶) for the two concentrations of sauces, respectively. At 0.05 confidence level, the t‐tabulated value was greater than the t‐calculated value (2.09 > 0.01), showing that there was no significant difference between the general quality characteristics of the AYB sauce and the conventional soy sauce.

PRACTICAL APPLICATIONS

The product AYB sauce made from the solid state fermentation of African yam beans (an underutilized Nigerian legume) can be used as condiment in preparation of foods (gravies, soups, stews, jollof and fried rice, pastry fillings, etc.) at homes, restaurants and fast food companies. The commercial production of the sauce will help in the reduction of the pressure on soybeans, which is the major raw material for the production of soy sauce, and increase the utilization of the crop and income of the farmers of AYB.

     

THE EFFECT OF PRETREATMENT OF SHREDDED CELERIAC USING SOLUTIONS OF ENZYMATIC BROWNING INHIBITORS ON THE QUALITY OF MINIMALLY PROCESSED PRODUCT

ABSTRACT

The study investigated the effect of soaking celeriac flakes in solutions containing various concentrations of enzymatic browning inhibitors on the quality of stored minimally processed product. Ascorbic acid (0.2–0.5%), 4‐hexylresorcinol (0.003–0.01%), sodium chloride (0.1–0.5%) and sodium lactate (2–3%) were used as browning inhibitors. On the basis of the conducted tests, it was found that among the applied browning inhibitors, only ascorbic acid had an advantageous effect on the quality of stored celeriac flakes. Along with an increase in its concentration in the solution (0.2–0.5%) used for the pretreatment of the flakes, the value of color parameter a* decreased, while the value of parameter b* increased. At the concentration of ascorbic acid in the solution exceeding 0.25%, flake color in the sensory examination was evaluated as desirable. An increase of ascorbic acid concentration in the solution in the range from 0.2 to 0.4% resulted in a decrease in the total mesophilic and psychrophilic bacteria counts, respectively, by 3 and 1 log cfu/g of the stored product.

PRACTICAL APPLICATIONS

Minimal processing of celeriac provides convenience for consumers and many economic benefits for producers. Minimal processing of celeriac can induce disadvantageous changes in tissue, which may lead to darkening of the flakes and deterioration of product sensory attributes. Moreover, shredded raw material constitutes an excellent medium for the development of microorganisms. This article contains information about the effectiveness of enzymatic browning inhibitors for extending the shelf life of celeriac flakes. We show a range of concentrations of inhibitors, which improve the preservation of color, intrinsic taste and microbial quality of minimally processed celeriac.

     

CHANGES DURING FERMENTATION AND PROPERTIES OF SOM-FUG PRODUCED FROM DIFFERENT MARINE FISH

ABSTRACT

Microbiological, chemical and physical changes of Som‐fug produced from six marine fish during fermentation were monitored. During the fermentation (0–72 h) at 30C, the increase in lactic acid bacteria (LAB) count and total acidity (TA) with the concomitant decrease in pH was observed. After the fermentation was completed, Som‐fug samples contained 1.5–7.9 × 10⁹ cfu/g LAB count and TA ranging from 2.00 to 2.28% with the pH range of 4.53–4.60. Trimethylamine N‐oxide content decreased, whereas trimethylamine content increased throughout the fermentation (P < 0.05). Proteolysis of Som‐fug proteins and lipid oxidation occurred during fermentation. As the fermentation proceeded, hardness, adhesiveness, springiness and cohesiveness of all samples increased, and L*, a*and b*values also increased (P < 0.05). Generally, Som‐fug produced from bigeye snapper showed a greater acceptability than those produced from other species. However, its acceptability was slightly lower than a commercial Som‐fug produced from freshwater fish (P < 0.05).

PRACTICAL APPLICATIONS

This research indicates that some marine fish can be used as the raw material for Som‐fug production with the quality almost comparable to those prepared from fresh water fish, which are commercially availalble. Therefore, the improvement of process for Som‐fug production from marine fish should be further conducted to obtain the better quality and higher acceptability. As a consequence, Som‐fug from marine fish with the high nutritive value can become a novel product for the consumers.

     

Detection of hazelnut oil in virgin olive oil by a spectrofluorimetric method

The possibilities of a spectrofluorimetric method joined to multivariate analysis to assess the genuineness of olive oil in admixtures with hazelnut oils were studied. Virgin olive, virgin hazelnut and refined hazelnut oil samples and admixtures between them at 5, 10, 15, 20, 25 and 30% adulteration were analysed at _ex=350 nm. The precision of the method, in terms of repeatability and internal reproducibility, was established by means of the analysis of a virgin olive oil sample under different conditions, the RSD showing values less than 10%. Raw data of the spectra were subjected to mathematical treatment by calculation of the first derivative, selection of the maximum values and application of one-way ANOVA, to assess the most prominent variables in the discrimination process. The response to the addition of adulterant was linear, adjusted-R²=0.99 for virgin olive and refined hazelnut oil mixtures, and 0.98 for virgin olive and virgin hazelnut oil mixtures. Stepwise linear discriminant analysis applied to each admixture separately and to the whole set of samples allowed 100% correct classifications.