EFFECTS OF PRETREATMENT WITH ROSEMARY (ROSMARINUS OFFICINALIS L.) IN THE PREVENTION OF LIPID OXIDATION IN SALTED TILAPIA FILLETS

ABSTRACT

To delay lipid oxidation during meat processing, synthetic antioxidants have been used in the food industry, but the consumers' concern over their toxicity increased interest in research with natural antioxidants. The aim of this work was to analyze the water activity (A_w), thiobarbituric acid reactive substances (TBARS), moisture and trichloroacetic acid‐soluble nitrogen (TCASN) in brined tilapia fillets treated or pretreated with natural rosemary extract (Rosmarinus officinalis) and stored for 240 days at ?18C. Higher A_w (0.900 ± 0.010) and moisture (70.13 ± 0.20) values were observed in the pretreated fillets. The TBARS values in the treatment (3.31 ± 0.79) and pretreatment (3.39 ± 0.53) were half the value of the control treatment (6.14 ± 1.21) at 240 days. Statistical differences were observed in TCASN values in 180 (0.112 ± 0.020) and 240 (0.132 ± 0.017) days, with the pretreatment showing a more protective effect in protein oxidation. In this study, rosemary proved to be protective during the frozen storage, especially when its extract was used as pretreatment, before the salting process.

PRACTICAL APPLICATIONS

Fish consumption is highly elastic, because the annual average consumption of seafood per person in Brazil is only 6.8 kg. The federal government has set a goal to increase it to 12 kg by 2007. Salting is an older food preservation process still used today, and is extremely important because, despite advances in food technology, increased monitoring and improved knowledge, it is emphasized as an easy, cheap and effective process that does not require refrigeration. Tilapia is a highly prolific fish, with a production volume that is increasingly higher each year in Brazil. Therefore, it calls for interesting research to allow an increased shelf life for this species.

     

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.

     

Effect of natural antioxidants on oxidative stability of cooked, refrigerated beef and pork

ABSTRACT:  The effect of grape seed extract (GS; 0.01% and 0.02%), oleoresin rosemary (OR; 0.02%) and water-soluble oregano extract (WS; 0.02%) on oxidative and color stability of cooked beef and pork patties stored at 4 °C for 8 d was determined. Fresh beef or pork lean and trim were ground, mixed (30% fat), and divided into 5 portions. Antioxidants mixed with salt (2%) were added. Patties were formed, cooked to an internal temperature of 71 °C, overwrapped in PVC, and stored at 4 °C. Lipid oxidation, assessed using thiobarbituric acid reactive substances (TBARS) and sensory evaluation, instrumental and visual color, and pH were determined after 0, 2, 4, 6, and 8 d. Based on TBARS values and off-odors associated with lipid oxidation such as rancidity, wet cardboard (for beef patties), and grassy (for beef and pork patties), grape seed extract resulted in the best antioxidant activity in both meat species. It did not change instrumental color measures of redness, yellowness, or color intensity, and appeared to reduce visual green discoloration in beef patties. The higher GS concentration (0.02%) exhibited more antioxidant activity than the lower concentration (0.01%). Therefore, grape seed extract at 0.02% has the potential to reduce oxidative rancidity and improve shelf life of refrigerated cooked beef and pork patties.     

迷迭香提取物对冷藏调理猪肉饼品质的影响

研究不同剂量迷迭香提取物对4 ℃冷藏调理猪肉饼抗脂肪氧化、抑菌能力及品质特性的影响。将0.03%、0.06%和0.09%的迷迭香提取物分别添加到调理猪肉饼中,测定其在10 d冷藏过程中硫代巴比妥酸值、菌落总数、pH值、颜色（L*、a*、b*值）、出品率和感官指标的变化。结果表明：与对照组相比,添加迷迭香提取物的各处理组具有显著的抗脂肪氧化效果和更高的出品率（P＜0.05）,效果与添加0.02%二丁基羟基甲苯相当。迷迭香提取物添加量为0.06%和0.09%的处理组在冷藏7 d后表现出显著的抑菌能力（P＜0.05）,这两组的pH值在冷藏期间显著低于对照组（P＜0.05）。迷迭香提取物添加量为0.06%的猪肉饼在冷藏4 d后红度值（a*）与对照组相比显著升高（P＜0.05）,迷迭香提取物添加量为0.09%的猪肉饼在10 d冷藏过程中亮度值（L*）显著低于对照组（P＜0.05）,而这两组猪肉饼的黄度值（b*）在冷藏期间均显著高于对照组（P＜0.05）。此外,猪肉饼的香气、质地和总体可接受程度均没有随迷迭香提取物添加量的增加而发生显著变化（P＞0.05）。可见,迷迭香提取物在调理猪肉饼中具有较好的抗氧化和抑菌效果,并且在一定程度上能改善肉饼颜色,而对肉饼的感官品质不会造成不良影响。     

Antioxidant Action of Borage, Rosemary, Oregano, and Ascorbic Acid in Beef Patties Packaged in Modified Atmosphere

ABSTRACT: Beef patties containing either ascorbic acid, rosemary, oregano, or borage were evaluated for storage stability at 2 ± 1 °C, by measuring a* and H* values, surface metmyoglobin, TBARS, psychrotrophic bacteria counts, and sensory off‐odor and discoloration. All of the antioxidants (except ascorbic acid) reduced (p < 0.01) TBARS formation, which was totally inhibited by borage. Myoglobin oxidation and color fading were inhibited (p < 0.01) by rosemary, oregano, and borage. Microbial growth showed insignificant differences among treatments. Sensory results showed that rosemary, oregano, and borage extended beef patties' shelf life from 8 to 12 d, while rosemary plus ascorbic acid extended shelf life an additional 4‐d period.     

Extension of the display life of lamb with an antioxidant active packaging

Fresh lamb steaks were treated with three different preparations of natural antioxidants: one group was packaged with a rosemary active film, the second group was packaged with an oregano active film, and the third group was sprayed on the meat surface with a rosemary extract before packaging in a high-oxygen atmosphere. Samples were stored under illumination at 1 ± 1 °C for 13 days. Metmyoglobin formation, lipid oxidation (TBARS), instrumental colour (CIE a^*), psychrotrophic bacterial counts (PCA), sensory discolouration and off-odour were determined. The use of a rosemary extract, a rosemary active film or an oregano active film resulted in enhanced oxidative stability of lamb steaks. Active films with oregano were significantly more efficient than those with rosemary, exerting an effect similar to that of direct addition of the rosemary extract; in fact, they extended fresh odour and colour from 8 to 13 days compared to the control.     

Inhibition of Lipid Oxidation and Rancidity in Precooked Pork Patties by Radical‐Scavenging Licorice (Glycyrrhiza glabra) Extract

This study investigated the efficacy of licorice extract (LE) to curtail lipid oxidation and protect sensory attributes of ground pork during refrigerated and frozen storage. Pork patties (20% fat) were formulated with 0%, 0.02%, 0.05%, and 0.1% (meat basis) LE or rosemary extract (RE) as comparison or 0.01% (fat basis) BHA with 0 or 1.5% NaCl. Raw and precooked (75 °C) patties were packaged in polyvinylchloride overwrapped trays and stored at 2 °C up to 7 and 14 d, respectively, or at –20 °C up to 6 mo. Lipid oxidation (thiobarbituric acid‐reactive substances [TBARS]) and sensory attributes of stored patty samples were evaluated, radical scavenging activity of the LE was measured, and the active phenolic compounds were identified. Cooking yield (<85%) was similar among antioxidant treatments, and lipid oxidation was minimal in refrigerated or frozen raw samples. However, TBARS values in refrigerated precooked control patties (0.22 mg/kg) rose to 9.3 to 9.4 mg/kg after 14 d, compared to 3.4 to 4.4 and 4.4 to 6.9 mg/kg in patties treated with 0.1% LE and RE, respectively. In frozen precooked samples, TBARS (0.22 mg/kg) increased to 1.3 mg/kg (P < 0.05) in control patties after 6 mo and had no significant change in patties treated with 0.1% LE or 0.01% butylated hydroxyanisol. Sensory panel evaluation confirmed strong inhibition of rancidity production by LE, corroborating its remarkable antiradical activity due to the presence of multiple phenolics. The results indicate that licorice has great potential as a natural antioxidative additive to extend the shelf‐life of precooked pork.     

ANALYSIS OF TEXTURE OF BONELESS, FULLY FRIED BREADED CHICKEN PATTIES AS AFFECTED BY PROCESSING FACTORS

ABSTRACT

Battered and breaded, fully cooked, boneless chicken patties were analyzed based on processing variables (substrate, breading, rethermalization method, shape) and six objective texture attributes. Analysis of variance compared both individual samples and main effects, while statistical cluster analysis classified products based on their independent characteristics and the objective texture attributes. One sample (baked, crackermeal, all meat, nuggets) was significantly higher in most textural attributes. The soy‐containing samples were texturally similar. Breading and shape were not significantly different for the main effects of crust fracture force and work. Samples were sorted into clusters: cluster 1 characterized by oat bran breading, cluster 2 by crackermeal breading and soy‐containing substrate, cluster 3 by crackermeal and all‐meat substrate, and cluster 4 by Japanese bread crumbs and patty shape. Statistically classifying breaded chicken patties could lead to the development of a reliable, statistically based and easy‐to‐implement process that would aid quality control and product development in the meat industry.

PRACTICAL APPLICATIONS

Characterization of the textural attributes of breaded meat patties such that differentiation could be achieved with a common instrument (texture analyzer) could provide a reliable and easy‐to‐implement method to assess the quality of texture in meat products that would be beneficial to the meat industry for both quality control and product development purposes.

     

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.

     

Extension of the display life of lamb with an antioxidant active packaging

Fresh lamb steaks were treated with three different preparations of natural antioxidants: one group was packaged with a rosemary active film, the second group was packaged with an oregano active film, and the third group was sprayed on the meat surface with a rosemary extract before packaging in a high-oxygen atmosphere. Samples were stored under illumination at 1 ± 1 °C for 13 days. Metmyoglobin formation, lipid oxidation (TBARS), instrumental colour (CIE a¹), psychrotrophic bacterial counts (PCA), sensory discolouration and off-odour were determined. The use of a rosemary extract, a rosemary active film or an oregano active film resulted in enhanced oxidative stability of lamb steaks. Active films with oregano were significantly more efficient than those with rosemary, exerting an effect similar to that of direct addition of the rosemary extract; in fact, they extended fresh odour and colour from 8 to 13 days compared to the control.     

Effect of plant phenolics,tocopherol and ascorbic acid on oxidative stability of pork patties

BACKGROUND: There is great interest in the use of naturally occurring antioxidants to delay oxidation in meat products. The effect of rosemary extract (RE), green tea extract (TE), tocopherol, trolox, ascorbic acid (AA) and ascorbyl palmitate (AP), at levels of 50–200 ppm of antioxidant components, on colour (CIE L*a*b*), lipid (TBARS) and protein oxidation (thiol groups) in fresh, frozen and cooked pork patties during illuminated chill storage was investigated. Individual components of RE and TE were also tested. RESULTS: RE, TE, AP, tocopherol and trolox equally inhibited lipid oxidation in fresh and frozen patties, whereas for cooked patties RE was most effective. AA stimulated lipid oxidation. No dose effect in the range of 50–200 ppm was found for fresh and frozen patties, whereas for cooked patties higher doses of RE and TE more efficiently prevented lipid oxidation. Protein oxidation was hardly influenced by antioxidant treatment. Colour stability decreased as follows: tocopherol, AA and AP > RE and TE > trolox. Antioxidant properties of the extracts and their major antioxidant components were comparable. CONCLUSION: The relative effect of the antioxidants depends on the oxidation parameter assessed, the applied dose and the hydrophilic/lipophilic character. Copyright © 2009 Society of Chemical Industry     

CORRELATION BETWEEN DIELECTRIC PROPERTIES AND FRESHNESS OF LEAF VEGETABLES

ABSTRACT

The correlation between the dielectric properties and the freshness of leafy vegetables was studied to evaluate the quality nondestructively. The dielectric properties were studied on four kinds of leaf vegetables with two plate electrodes during storage at room temperature. The results show that the dielectric constants and parameters for freshness decreased during 3‐day storage of leaf vegetables. A significant correlation between the dielectric properties and freshness of four vegetables was observed. It is possible to evaluate the quality of vegetables nondestructively by determination of dielectric properties.

PRACTICAL APPLICATIONS

Studying the dielectric properties of food is of current interest and may potentially assist the prediction of quality as well as application to the processing and preparation of food. Dielectric technologies are widely adopted and provide unique advantages for predicting storage, electric processing and quality inspection. Innovative assaying of dielectric properties to evaluate the quality of vegetables nondestructively is proposed in this article. Inspection by using the electric physical properties provides methodology for the automation and precision control of food processing.

     

EFFECTS OF DIFFERENT SALT CONTENTS ON SOME QUALITY CHARACTERISTICS DURING PROCESSING OF DRY‐CURED TURKISH PASTIRMA

ABSTRACT

This study examined the effects of different salt contents (3, 6 and 9%) during process stages on physicochemical, lipid oxidation and microbial quality of a dry‐cured meat product, past?rma, throughout 21 days of processing. Significant changes in moisture content, NaCl content, pH and water activity (a_w) were observed in past?rma after the third drying and pasting stages. There were significant decreases (P < 0.05) in objective color characteristics (L*, a* and b*) between raw material and final product for all past?rma samples. However, no significant effect of salt level (P > 0.05) was detected on L* and a*. Salt level significantly (P < 0.05) affected thiobarbituric acid‐reactive substances (TBARS) formation, which was lower in low‐salt past?rma samples, while the combination of salting, drying and pressing stages increased TBARS values in high‐salt past?rma samples. Higher salt content (6% and 9%) and last drying resulted in reduction of microbial count.

PRACTICAL APPLICATIONS

Salt (NaCl) is an important agent in inhibiting microbial growth, reducing water activity and imparting a salty taste to dry‐cured meat products such as ham and past?rma. Salt content in past?rma varies from 5% to 10% in the final product and has an impact on product quality parameters. The effects of different NaCl contents (3, 6 and 9%) and processing stages on pH, water activity (a_w), color parameters, lipid oxidation and microbial count were studied during processing of past?rma. Low‐salt concentration had some negative impacts on past?rma characteristics, giving high a_w, pH and microbial count, but low Thiobarbituric acid‐reactive substances value and NaCl content. Drying, pressing and pasting with çemen mixture during past?rma processing had a positive impact on reduction of moisture, a_w and microbial count.

     

花椒提取物对调理猪肉饼冷藏期间品质的影响研究

探究不同添加量的花椒提取物对调理猪肉饼冷藏期间品质及氧化程度的影响。将0.01%、0.02%和0.03%的花椒提取物添加到调理猪肉饼中,研究其在1、4、7、10 d冷藏期间的pH、颜色、质构、硫代巴比妥酸值(thiobarbituric acid reactive substance,TBARS)和巯基值的变化,并与0.02%二丁基羟基甲苯(butylated hydroxytoluene,BHT)作比较。研究结果表明,添加花椒提取物对调理猪肉饼冷藏期间的pH、颜色无显著影响(p>0.05),在一定程度上降低了其硬度和咀嚼性。此外,添加花椒提取物可显著降低猪肉饼脂肪氧化和蛋白质氧化程度(p<0.05)。当添加量为0.01%和0.02%时,花椒提取物处理组抑制脂肪氧化的效果与0.02%的BHT效果相当,而当添加量增加至0.03%时,花椒提取物组抗脂肪氧化效果优于0.02%的BHT,且其蛋白氧化程度在整个冷藏期间均显著低于对照组(p<0.05),表明花椒提取物可有效抑制猪肉饼中脂肪和蛋白质氧化,其中0.03%花椒提取物组效果最好,甚至优于0.02%的BHT。     

SHELF LIFE OF MEAT FROM PODOLIAN YOUNG BULLS IN RELATION TO THE AGING METHOD

ABSTRACT

In order to achieve an adequate level of tenderness while reducing chilling and technological losses, the effect of two aging methods (on the carcass or under vacuum packaging) on the shelf life (5‐day retail display) of meat from eight Podolian young bulls (16–18 months old) was assessed. Most of the recorded variables were not affected by the interaction aging method × time of display (P > 0.05). These results indicate that the shelf life of meat from Podolian cattle was not influenced by the aging method. In both aging methods, redness a* increased after 1 day of display and subsequently decreased (P < 0.001). Lipid oxidation and total aerobic mesophilic count increased significantly during retail display (P < 0.001). We concluded that vacuum packaging may be conveniently used for the maturation of primal cuts from Podolian carcasses to save energy and space, and prevent chilling and technological losses.

PRACTICAL APPLICATIONS

The aging under vacuum of individual bovine primal cuts can save energy and space as well as prevent chilling and technological losses generally occurring when meat is aged on carcass. This method had no negative effects on meat shelf life. Thus, it may be conveniently used to apply sufficiently extended maturation periods to the meat, which are needed to increase tenderness to a level, which is not prejudicial to product acceptability.

     

CHANGES IN APPARENT VISCOSITY AND VITAMIN C RETENTION DURING THERMAL TREATMENT OF BUTTERNUT SQUASH (CUCURBITA MOSCHATA DUCH) PULP: EFFECT OF RIPENING STAGE

ABSTRACT

The effects that ripening stage have on the apparent viscosity and ascorbic acid retention in squash pulp exposed at cooking process were analyzed. Total soluble solids contents were taken as indicative of ripening degree. In the raw material, water contents ranged from 79 to 96%, but no significant differences were observed among samples grouped as unripe, ripe and overripe. The ascorbic acid contents of pulp increase with increases in soluble solids contents. Pulp from unripe and ripe squash had similar apparent viscosity values; however, lower viscosity values were obtained in pulp from overripe squash. During heat treatment, significant changes in the apparent viscosity values of pulp from unripe and ripe squash were observed. Heat penetration properties of squash pulp indicate correlation between the inverse slope of the straight portion in the heat penetration curves on a semilog plot (fh) and thermal diffusivity values (α) with dry matter content, but no correlation was found with squash maturity degree. High ascorbic acid retention (82%) in pulp held for 30 min at 95C was found independently of squash maturation degree.

PRACTICAL APPLICATIONS

Knowing the rheological behaviour and the ascorbic acid retention of butternut squash pulp during cooking process could be used as a valuable information previously to make decisions for use this crop as a food supply.

     

SHELF-LIFE SIMULATION OF PACKAGED RICE CRACKERS

ABSTRACT

Two varieties of rice crackers (RC‐1 and RC‐2) were packaged in two types of packaging materials, polyethylene and polypropylene pouches, and stored at 30C/75% RH and 30C/85% RH to simulate actual storage conditions and determine shelf‐life. The main composition differences in the samples were in their fat content (1.87% for RC‐1 and 21.09% for RC‐2) and initial moisture content (4.12% for RC‐1 and 2.28% for RC‐2). The shelf‐life of this product is mainly affected by moisture adsorption as evidenced by sensory evaluation. Guggenheim‐Anderson‐de Boer (GAB) model was used to fit the moisture sorption isotherm. Good precision of fit was found as measured by a determination coefficient (R²) close to 1. The shelf‐life was then predicted based on the relationship between permeability coefficient of the packaging materials and moisture adsorbed by the rice crackers determined by the GAB equation. The validation of the simulations against the experimental shelf‐life gave R² of 0.90 and 0.51, and root mean square error of 2.93 and 5.20 for RC‐1 and RC‐2, respectively. The simulation model was found to be applicable for a rapid and accurate shelf‐life prediction of RC‐1. However, a large difference between experimental and simulated shelf‐life of RC‐2 was probably because the moisture content may not be the only parameter influencing the shelf‐life of the RC‐2 samples. Other factors may also significantly affect the shelf‐life characteristics of the packaged rice crackers.

PRACTICAL APPLICATIONS

For a low‐moisture food product, actual storage testing by a long‐term stability study involves storing a packaged product under typical storage conditions and examining the product at regular time intervals. The testing is costly and time consuming, since most low‐moisture food products have a shelf‐life of several weeks or even months. This paper describes the shelf‐life prediction of two varieties of rice crackers having different compositions using a simulation model based on the relationship between barrier property of the packaging materials and moisture adsorbed by the rice crackers determined by the Guggenheim‐Anderson‐de Boer (GAB) model. The shelf‐life simulation provides a powerful support tool for shelf‐life estimation and packaging development.

     

VARIETAL AROMA COMPOUNDS OF VITIS VINIFERA CV. KHAMRI GROWN IN TUNISIA

ABSTRACT

The aroma composition of the grape juice of Khamri, a native variety of Vitis vinifera grown in Tunisia, was investigated for the first time. A total of 27 free and 20 glycosidically bound compounds were identified by gas chromatography‐mass spectrometry. According to the obtained results, the aroma compounds were C6 alcohols, benzene compounds, terpenes, acids and norisoprenoids. On the basis of gas chromatography‐olfactometry, these compounds were grouped, according to volatiles exhibiting the identical odor quality, into 10 groups of the same character (aromatic series) as a way of establishing an aroma profile for the studied variety. The high glycosidically bound norisoprenoid concentrations and the absence of the bound form of the acids were a positive factor for the Khamri variety potential aroma.

PRACTICAL APPLICATIONS

This article aimed on the identification of the unknown Tunisian grapevine varieties that are very well adapted to the arid conditions and that could have a good quality. The discovery of unknown autochthonous grapevine varieties with good aroma and pomological characteristics could be of great importance for the agriculture sector all over the world especially the arid regions.