Application and assessment of extruded edible casings manufactured from pectin and gelatin/sodium alginate blends for use with breakfast pork sausage

Casings formed from pectin (PN) containing 2.5% and 5% corn oil (CO) and olive oil (OO) and gelatine/sodium alginate blends (GSAB) containing 2.5% CO and OO respectively were used for sausage manufacture. Mechanical properties and water content of casings were assessed prior to application. Following sausage manufacture, product quality and shelf-life evaluation were assessed in terms of sensory attributes, instrumental colour, moisture loss and lipid oxidation. All manufactured casings were of good quality and initially produced intact and stable sausage products. However, with time, shrinkage of products occurred where GSAB casings were used. Sensory analysis of sausages showed that PN casings were more preferred to GSAB casings for sausage manufacture. CIE colour analysis supported sensory evaluation. Water losses from sausages using GSAB casings were lower compared to sausages using PN casings due to GSAB casings having higher ability to trap and absorb water compared to PN casings. Lipid oxidation developed over time for all sausage products, however, sausages manufactured using GSAB casings containing both CO and OO at 2.5% had better oxygen barrier properties compared to sausages manufactured using PN containing the same concentration of emulsified oils. Sausages manufactured using casings containing OO were more prone to lipid oxidation than those using CO. Importantly, sausages manufactured using PN casings containing 5.0% CO were extremely stable to lipid oxidation over a six day storage period and significantly, were <1 on the TBARS numbers scale.     

人造胶原肠衣的研究进展

肠衣作为食品包装材料,对维持肉制品的品质、延长货架期具有重要作用。随着肠衣需求量的增加,天然肠衣市场供不应求,为人造肠衣的出现和发展提供了机会。其中人造肠衣包括塑料肠衣、纤维素肠衣和胶原肠衣。在加工过程中每种肠衣都体现出各自的特点同时存在不同的亟待解决的问题。人造胶原肠衣在可食性、收缩性、黏着性等性能方面与天然肠衣相似,在资源稳定性和食品安全性等方面优于天然肠衣。胶原肠衣兼有天然肠衣和人造肠衣两者的优点,因此具有非常大的市场前景。本文在综述了肠衣类型的基础上,对比了国内外胶原肠衣的研究进展,总结了胶原肠衣的制备方法,并对胶原肠衣尤其是水产胶原肠衣的发展前景进行了展望,以期对胶原肠衣的研究提供理论基础。     

Dry-fermented chicken sausage produced with inulin and corn oil: Physicochemical,microbiological, and textural characteristics and acceptability during storage

This study aimed to evaluate the effect of oil content reduction and the addition of inulin as a partial oil substitute on the physicochemical, microbiological, and textural characteristics and acceptability during the storage (4 °C for 45 days) of dry-fermented chicken sausage produced with corn oil. Reducing the oil content did not influence the characteristics evaluated but tended to produce sausage with a dark reddish coloration. The addition of inulin did not change the physicochemical and microbiological parameters or the acceptability of the products, but resulted in an altered texture profile and a tendency toward lighter and less reddish coloration, similar to products with standard oil content. Fermented chicken sausages produced with standard amounts of corn oil, reduced amounts of corn oil, and inulin as a partial oil replacement remained stable without a significant loss of physical, chemical, microbiological, or sensory attributes during storage at 4 °C for 45 days.     

Alternative fatty food simulants and diffusion kinetics of nylon 12 food packaging.

The migration of laurolactam and cyclic di- and trimer of nylon 12 was assessed using three different films and five food simulants (olive oil, isooctane, 95% ethanol, 50% ethanol, water). Substitute test conditions for migration into olive oil according to European Union Directive EC/97/48 were applied using 95% ethanol and isooctane. Results showed that 95% ethanol overestimated while isooctane underestimated the respective migration into olive oil. Water was the best olive oil substitute, as migration of laurolactam into water and olive oil using the same temperature gave similar results. Additionally, diffusion kinetics of laurolactam were investigated by migration kinetic studies using isooctane and olive oil. Diffusion coefficients determined with isooctane were significantly higher than those found using olive oil. It was proved that isooctane had an interaction and olive oil was inert to the polymer. The diffusion conductance parameter, A(p), for nylon 12 determined using olive oil ranged from 0.3 to 0.6.     

Packaging and storage studies on double-filtered groundnut oil

Packaging and storage studies of double-filtered groundnut oil was carried out in different multilayer film pouches based on non-nylon, nylon and polyester (PET) layers and PET bottles at 27° C and 65% relative humidity (RH) and 38° C and 90% RH. The groundnut oil keeps better in multilayer film pouches consisting of nylon and PET films and PET bottles than in non-nylon-based film pouches under both conditions.

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Verpackung und Lagerung von doppelt filtriertem Erdnußöl

Zusammenfassung Es wurden Untersuchungen über die Lagerfähigkeit von doppelt filtriertem Erdnußöl in Polyesterflaschen und in Beuteln aus Verbundfolien mit und ohne Nylon sowie mit Polyester als Barriereschicht durchgeführt. Die Lagerung fand bei 27 °C, 65% relative Feuchtigkeit und 38 °C, 90% relative Feuchtigkeit statt. Die Haltbarkeit des Öls in den Flaschen und Beuteln mit Barriereschichten war wesentlich besser als in den Beuteln ohne Nylon-Schicht.

     

Inactivation of classical swine fever virus in porcine casing preserved in salt

Pig intestines used for the production of natural sausage casings may carry classical swine fever (CSF) virus. Feeding pigs with human food waste that contains pig casings may then spread the virus to CSF-free animals. Casings derived from a pig experimentally infected with CSF by dosing with 10(6) tissue culture infectious doses (TCID50) of the highly virulent CSF virus strain "Koslov", were treated with phosphate supplemented or citrate supplemented NaCl, instead of with NaCl alone, which is the standard preservation treatment for casings. Treated casings were stored for 30 days at either 4 degrees C or 20 degrees C. After storage the casings were fed to 16 susceptible pigs. CSF infection was confirmed in the four animals that had been fed casings treated with citrate supplemented salt and stored at 4 degrees C. All other animals remained healthy. It is therefore possible to avoid the inadvertent spread of CSF virus via porcine sausage casings by treating casings with phosphate supplemented salt and storing them for 30 days at temperatures over 4 degrees C.     

Effect of food ingredients and selected lipids on the physical properties of extruded edible films/casings

Films/casings produced using pectin (PN) and gelatin/sodium alginate blends (GSAB) containing 2.5 and 5% added corn oil (CO) or olive oil (OO) and non‐oil containing were manufactured using extrusion technology. Films/casings formed from PN and GSAB had great difference in properties of tensile strength, elongation, Young's modulus and puncture resistance. Quality and stability of films/casings were greatly enhanced on addition of oils. However, an oil addition of 2.5% was identified as optimal while 5% decreased the final films/casings quality. Oil addition increased (P < 0.05) films/casings thicknesses. Oil addition also decreased (P < 0.05) tensile strength, puncture resistance, Young's modulus and tear resistance of films/casings but increased their elongation properties, with the exception of converse effect of 2.5% CO on two films/casings. Olive oil and CO both reduced (P < 0.05) water vapour transfer rate (WVTR) of films/casings. However, no significant difference between films using different concentrations of oil was observed with respect to WVTR.     

Thermodynamics of partitioning of allyl isothiocyanate in oil/air,oil/water,and octanol/water systems

The thermodynamics of partitioning of allyl isothiocyanate (AITC) in oil/air, oil/water, and octanol/water systems were investigated using the van’t Hoff approach with olive and canola oils as model food oils. The partition coefficients were determined by phase ratio variation method at temperatures between 4 and 50 °C. AITC showed much stronger partitioning into oil or octanol phase than into air or water phase because of its strong hydrophobic nature. As temperature increased, the oil/air, oil/water, and octanol/water partition equilibria were shifted toward air, oil, and octanol phases, respectively. These partitioning behaviors are attributed that the air-to-oil transfer of AITC is an entropically unfavorable, enthalpy-driven spontaneous process, whereas both water-to-oil and water-to-octanol transfers are energetically unfavorable, entropy-driven spontaneous processes. Canola oil was found to be more effective as a solvent for AITC than olive oil in oil/air system but less effective in oil/water system.     

Reduction of Clostridium sporogenes spore outgrowth in natural sausage casings using nisin

Preservation of natural sausage casings using dry salt or saturated brine is regarded as sufficient to inactivate vegetative pathogenic non-spore-forming bacteria present on the casings. Although the outgrowth of bacterial spores is prevented by salt or saturated brine preservation, these spores will remain present and develop into vegetative cells when conditions are more favourable. To prevent subsequent outgrowth additional preservation measures should be implemented. In the experiments described the use of nisin was evaluated to reduce outgrowth of spores in desalinated casings. The bacteriocin nisin was chosen because of its known efficacy against spore-forming bacteria and their spores in various foodstuffs. Clostridium spore suspensions (Clostridium sporogenes, ATCC 3584) were used in two concentrations to inoculate three nisin concentrations (10, 50, 100 μg/mL) in water containing gamma-irradiated casings. Additionally, the binding of nisin to casings, using ¹⁴C-labeled nisin Z and subsequent availability of nisin were evaluated. Results demonstrate that nisin is partly reversibly bound to casings and can reduce the outgrowth of Clostridium spores in the model used by approximately 1 log₁₀ (90%). However, the biological relevance of these results needs to be determined further by conducting industrial trials before any recommendation can be made on the practical implementation of nisin in the preservation of natural sausage casings.     

Bentonite-Water Dispersions Simulate Foodservice Energy Consumption of Sausage Patties

A research project was initiated to determine if bentonite-water dispersions could simulate energy consumption of two sizes of sausage patties during convective heat processing. Based on sausage patty composition, a mixture containing 18.2% bentonite and 81.8% water was used. Procedures simulated those reported for three different oven loads of sausage patties. Energy consumption was monitored throughout heat processing and was expressed as watt hours per oven load and per pan. No significant differences were found between sausage and bentonite patties for the energy consumption required for each oven load. For this food product, bentonite-water dispersions were found to be effective food models which could substantially reduce food costs for research activities.     

肠衣制备及其对香肠品质的影响研究进展

香肠是肉制品的典型代表, 且因其独特的风味而深受人们喜爱。随着生活水平的提高, 人们对健康饮食有了更高的要求, 给提高香肠品质和安全性方面的研究带来了更大的挑战。肠衣作为香肠的包装材料, 对维持香肠品质和延长其货架期具有重要作用, 是香肠必不可少的一部分。近年来, 肠衣对香肠加工和贮藏过程中的感官品质、理化指标、风味品质和安全性等方面的影响, 已成为研究热点。本文对肠衣的分类以及肠衣对香肠的品质和安全性的影响进行了综述, 着重考察了肠衣对香肠的色泽、风味品质、pH、生物胺含量、多环芳烃含量、脂肪氧化和微生物方面的影响, 为香肠加工过程中肠衣的选择, 以及香肠品质改善和安全性的提高提供理论依据。     

Migration of fluorochemical paper additives from food-contact paper into foods and food simulants

Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water–ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg^?1 popcorn after popping and butter contained 0.1 mg kg^?1 after 40 days at 4°C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.     

Comparison of Bacteriological Status During Ripening of Traditional Fermented Sausages Filled into Different Diameter Artificial Casings

The ripening process of fermented sausages is affected by diameter and type of sausage casings, and depends on changes in the microflora, important from hygienic and technological aspects. The aim of this study was to compare the bacteriological status sausages which were stuffed in artificial collagen sausage casings of different diameters (35 mm and 60 mm) during ripening and drying. The sausage stuffing was the same, as was the uncontrolled ripening conditions. In bigger diameter sausages, significantly higher average total bacterial count, enterobacteria and lactic acid bacteria counts were found than in smaller diameter sausages.     

Virus inactivation by salt (NaCl) and phosphate supplemented salt in a 3D collagen matrix model for natural sausage casings

Due to possible presence and spread of contagious animal viruses via natural sausage casings the international trade in these food products is subject to veterinary and public health requirements. In order to manage these restrictions we determined the effect of casing preservation on four highly contagious viruses for livestock: foot-and-mouth-disease virus (FMDV), classical swine fever virus (CSFV), swine vesicular disease virus (SVDV) and African swine fever virus (ASFV). We used an in vitro 3D collagen matrix model in which cells, infected with the four different viruses were embedded in a bovine collagen type I gel matrix and treated with either saturated salt (NaCl) or phosphate supplemented saturated salt at four different temperatures (4, 12, 20 and 25 °C) during a period of 30 days. The results showed that all viruses were faster inactivated at higher temperatures, but that stability of the various viruses at 4 °C differed. Inactivation of FMDV in the 3D collagen matrix model showed a clear temperature and treatment effect on the reduction of FMDV titres. At 4 and 12 °C phosphate supplemented salt showed a very strong FMDV inactivation during the first hour of incubation. Salt (NaCl) only had a minor effect on FMDV inactivation. Phosphate supplemented salt treatment increased the effect temperature had on inactivation of CSFV. In contrast, the salt (NaCl) treatment only increased CSFV inactivation at the higher temperatures (20 °C and 25 °C). Also SVDV inactivation was increased by phosphate supplemented salt, but salt (NaCl) treatment only resulted in a significant decrease of SVDV titre at a few time points. The ASFV results showed that both salt (NaCl) and phosphate supplemented salt were capable to inactivate ASFV within 48 h. In contrast to the other viruses (FMDV, CSFV and SVDV), ASFV was the most stable virus even at higher temperatures. The results obtained in this in vitro model underline the efficacy of a combined treatment using phosphate supplemented salt and storage at 20 °C or higher for a period of 30 days. This treatment may therefore be useful in reducing the animal health risks posed by spread of contagious animal viruses by international trade of natural sausage casings.     

Method of test and survey of caprolactam migration into foods packaged in nylon-6

An analytical method for the determination of the nylon-6 monomer caprolactam in foods is described. The foodstuff was extracted with ethanol : water (1:2) containing capryllactam as internal standard and the extract was defatted using hexane. The extract was analysed by liquid chromatography coupled with mass spectrometry. The test method was calibrated down to 0.7 mg kg^-1. The repeatability of the method was good, with a relative standard deviation of 9% at the 15 mg kg^-1 level. The method was demonstrated to be accurate in an independent external check sample exercise. The new method was applied to the analysis of 50 retail foodstuffs packaged in nylon-6. Caprolactam was detected and confirmed in nine of the 50 food samples, in the range 2.8-13 mg kg^-1. The presence of caprolactam was indicated in a further 15 samples, in the range 0.8-11 mg kg^-1, but these samples did not meet all of the five confirmation criteria applied. All migration levels (both confirmed and unconfirmed) were below the European specific migration limit for caprolactam, which is 15 mg kg^-1. The average migration for all 50 samples, setting non-detectables at half the limit of detection, was 2.6 mg kg^-1 with a standard deviation of 3.1 mg kg^-1 (n = 50). All samples found to contain detectable levels of caprolactam migration were for applications involving heating the food in the packaging. They were packs of, for example, sausage meat for which the food would have been heat processed in the nylon casing, or they were nylon pouches for heating foods by boiling, microwaving or roasting.     

Migration study of carvacrol as a natural antioxidant in high-density polyethylene for active packaging

The migration behaviour of low molecular weight compounds from food packaging materials is one of the key issues in assessing the possibility of use in such applications. The aim of this work was to study the migration of carvacrol (1% and 2% w/w) when added to high-density polyethylene. All materials were exposed to the food simulants olive oil and distilled water separately at 40°C and 25°C. Three significant variables influencing the migration process were considered: incubation temperatures, the initial concentration of antioxidant, and the type of simulant (oil and aqueous). The amount of carvacrol migrating to olive oil was significantly higher than in water because of the higher solubility of this antioxidant in oil. Experimental results agreed reasonably well with those obtained by the application of a simple model derived from Fick's Second Law. Carvacrol could therefore be used in active packaging formulations as its release from the polymer matrix can be controlled.     

Functional properties of protein isolate obtained from physic nut (<Emphasis Type="Italic">Jatropha curcas</Emphasis> L.) seed cake

Physic nut (Jatropha curcas L.) protein isolate was successfully achieved from physic nut seed cake by an alkaline extraction and followed by an isoelectric precipitation. The protein isolate had small amounts of phorbol esters, phytic acid, and saponin without any lectin. Its minimum and maximum solubility were at pH 4.0 and 12.0, respectively. Its water and oil binding capacities were 3.22 g water/g protein and 1.86mL oil/g protein, respectively. Its foaming capacity and emulsion activity showed high values in a range of basic pHs. Its foaming and emulsion stability values decreased with increasing time and exhibited high levels under basic pH conditions. Physic nut protein isolate had unique functional properties in water binding capacity, emulsion activity, and emulsion stability indicating an important role in food systems. It may be applied to salad dressing, mayonnaise, sausage, and meat products. Therefore, physic nut seed cake has a potential to be exploited as a novel source of functional protein for food or feed applications.     

Quality properties of sausage made with gamma-irradiated natural pork and lamb casing

Quality properties in emulsion-type sausage stuffed into irradiated natural casing were studied. Fresh salted and semidried natural pork and lamb casing was washed and irradiated at 0, 3, and 5 kGy by gamma-ray and emulsion-type pork sausage (Brattella Weiss Wurst) was manufactured. The sausage was stored in a 4°C refrigerator. The numbers of total aerobic bacteria, Enterococcus and coliform bacteria in the irradiated natural casing or sausage prepared from irradiated casing were significantly decreased or eliminated compared to those of the nonirradiated control. The D(10) values of total aerobic bacteria of the pork and lamb casing were 0.87 and 0.92 kGy, respectively. The vacuum-packaged sausages made with irradiated casings had a higher 2-thiobarbituric acid reactive substances value than that of the nonirradiated controls only at 5-day with pork casing and at 10-day with lamb casing. The total working force for shear of the sausages was decreased in both irradiated casings but the sensory evaluation showed no difference. Therefore, the gamma irradiation was a useful technique to sanitize the natural pork and lamb casings and to extend shelf-life, primarily microbial quality, of the sausage made with natural casings.     

Determination of thermal conductivity and convective heat transfer coefficient during deep fat frying of “Kroštula” dough

In this study, the influence of oil temperature, water migration and surface temperature of Krotula dough on convective heat transfer coefficient was investigated. The convective heat transfer coefficient during deep fat frying was determined at temperatures 160, 170, 180 and 190±1 °C. Heat transfer coefficient was the highest at the start of deep fat frying process; 579.12±2.46, 583.88±1.81, 597.05±1.10 and 657.91±0.95 W/m² K for 160, 170, 180 and 190 °C of oil temperature, respectively. The smallest heat transfer coefficient was in the case of setting up a uniform period of water migration from sample, which corresponded to surface temperatures slightly higher than 100 °C; 26.53±0.63, 14.42±0.56, 56.78±0.49 and 37.52±0.54 W/m² K for 160, 170, 180 and 190 °C of oil temperature, respectively. Higher oil temperature for deep fat frying increased values of heat transfer coefficient. A steady-state method was used to determine thermal conductivity of Krotula dough in temperature range of 40–70±1 °C. The thermal conductivity first increased with temperature and then after reaching maximum values decreased. The maximum value 0.5985±0.0196 W/(m K) was determined at 47.5 °C. The minimal value 0.4723±0.0192 W/(m K) was determined at 65 °C.     

Migration of fluorochemical paper additives from food-contact paper into foods and food simulants

Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water-ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg^-1 popcorn after popping and butter contained 0.1 mg kg^-1 after 40 days at 4°C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.