Survival of Lactobacillus delbrueckii UFV H2b20 in ice cream produced with different fat levels and after submission to stress acid and bile salts

The survival of Lactobacillus delbrueckii UFV H2b20 in three ice cream formulations (low fat, fat free and high fat) was evaluated after the processing and storage at ?16 °C. The survival of L. delbrueckii UFV H2b20 was not significantly affected (P > 0.05) in three ice cream formulations after processing. The same result was observed during storage for 40 days at ?16 °C. Cells of L. delbrueckii UFV H2b20 incorporated in three ice cream formulation survived when exposed to acid stress and bile salts. The results demonstrate that L. delbrueckii UFV H2b20 has potential for being used in ice cream and capacity to resist acid stress and to grow in the presence of bile salts. This demonstrates that reduction of fat in ice cream does not compromise the viability of L. delbrueckii UFV H2B20.     

Influence of Cape gooseberry (Physalis peruviana L.) addition on the chemical and sensory characteristics and mineral concentrations of ice cream

In this research, the influence of Cape gooseberry (CG) addition at different concentrations (5, 10 and 15%) on the physical, chemical and sensory properties and mineral contents of ice cream was investigated. The increment of CG concentration caused the decrease of fat, protein, pH and overrun values in ice cream, on the contrary it increased the total solid, ash, titratable acidity, viscosity values and first dripping and complete melting times. S contents of ice creams significantly increased with the CG addition. Moreover, CG increased K, and Na concentrations of ice cream, while lowered Ca and P contents. Mg contents of ice creams didn't change with CG addition (P > 0.05). Fe, Zn, Mn and Ni were determined as minor elements in ice cream samples and a significant increase was observed in Fe, Zn and Mn values (P < 0.05). The addition of CG did not affect Ni content of ice creams. The sensory results indicated that the ice cream containing 15% CG was the highest-scored by the panelists.     

Microbiological,chemical and sensory assessment of iced whole and filleted aquacultured rainbow trout

The effect of filleting on microbiological, chemical, and sensory properties of aquacultured freshwater trout (Onchorynchus mykiss) stored in ice was studied. Pseudomonads, H₂S-producing bacteria (including Shewanella putrefaciens) and Brochothrix thermosphacta were the dominant bacteria while, Enterobacteriaceae in lower counts were also found in the spoilage microflora of whole ungutted and filleted trout over an 18-day storage period in ice. Bacterial counts of whole ungutted trout were always lower than those obtained for filleted trout samples. Mesophilic counts for filleted and ungutted fish exceeded 7 log cfu/cm² after 10 and 18 days of ice storage, respectively. Of the chemical indicators of spoilage, trimethylamine (TMA) values of ungutted trout increased very slowly whereas for filleted samples higher values were obtained reaching a final value of 4.29 and 6.38 mg N/100 g, respectively (day 18). Total volatile basic nitrogen (TVB-N) values showed no significant increase for whole ungutted trout during storage reaching a value of 20.16 mg N/100 g (day 18) whereas for filleted fish a respective value of 26.06 mg N/100 g was recorded. Thiobarbituric acid (TBA) values of ungutted trout increased very slowly whereas for filleted samples higher values were obtained reaching a final value of 16.21 and 19.41 μg MA/g, respectively (day 18). Of the chemical indices used, none proved useful means of monitoring early freshness for ungutted and filleted trout freshness in ice. Sensory assessment using the EC freshness scale gave a grade E for up to 6 days for the ungutted trout, a grade A for a further 3 days and a grade B for an additional 6 days, after which trout was graded as C (unfit). Acceptability scores for odor, taste and texture of cooked ungutted and filleted trout decreased with time of storage. Results of this study indicated that the shelf-life of whole ungutted and filleted trout stored in ice as determined by sensorial and microbiological data is 15–16 and 10–12 days, respectively.     

High-pressure calorimetric evaluation of ice crystal ratio formed by rapid depressurization during pressure-shift freezing of water and pork muscle

The amount of ice nuclei formed during the pressure release is important for the final formation and development of ice crystals in pressure shift freezing (PSF) frozen products. In this study, a high-pressure (HP) calorimeter was used to evaluate the ratio of ice crystals instantaneously formed by rapid depressurization during PSF of pure water and pork muscle tissue. Experiments were carried out initial pressure levels of 62, 115, 157 and 199 MPa, with corresponding phase change temperatures of −5, −10, −15 and −20 °C, respectively (slightly higher than phase change point of water–ice I). The ice crystal ratio was determined based on calorimetric peak measured and heat balance. The evaluated regression relationship between observed ice crystal ratio (R_ice in %) and pressure (P, MPa) was R_ice–water = 0.115P + 0.00013P² (R² = 0.96, n = 9) for pure water, and R_ice–pork = 0.080P + 0.00012P² (R² = 0.95, n = 11) for pork muscle. Compared to other methods, the calorimetric evaluation does not require any of the pressure-related properties of the test sample. HP calorimetry can thus be used to evaluate ice crystal ratio for PSF of foods even though their pressure related properties may be unknown.     

Effect of gutting on microbiological,chemical, and sensory properties of aquacultured sea bass (Dicentrarchus labrax) stored in ice

The effect of gutting on microbiological, chemical, and sensory properties of aqua-cultured sea bass (Dicentrarchus labrax) stored in ice was studied. Pseudomonads and H₂S-producing bacteria (including Shewanella putrefaciens) were the dominant bacteria at the end of the 16-day storage period in ice for both whole ungutted and gutted sea bass. Brochothrix thermosphacta and Enterobacteriaceae were also found in the spoilage microflora of ungutted and gutted sea bass but their counts were always less than those of Pseudomonads and H₂S-producing bacteria. Bacterial counts of whole ungutted sea bass were always higher than those obtained for gutted sea bass samples. Mesophilic counts for gutted and ungutted fish exceeded 7 log cfu g⁻¹ after 9 and 15 days of ice storage, respectively. Of the chemical indicators of spoilage, TMA values of ungutted sea bass increased very slowly whereas for gutted samples higher values were obtained reaching a final value of 0.73 and 4.39 mg N 100 g⁻¹, respectively (day 16). TVB-N values showed no significant increase for whole ungutted sea bass during storage reaching a value of 27.7 mg N 100 g⁻¹ (day 16) whereas for gutted fish 36.9 mg N 100 g⁻¹ was recorded. TBA values remained low for ungutted sea bass samples until day 16 of storage, whereas for gutted fish were variable. Of the chemical indices used, none proved useful means of monitoring early ungutted and gutted sea bass freshness in ice. Sensory assessment using the EC freshness scale gave a grade E for up to 5 days for the ungutted sea bass, a grade A for a further 2 days and a grade B for an additional 4 days, after which sea bass was graded as C (unfit). Gutted sea bass was given a grade E for up to 3 days, a grade A for the 4–7th days, and a grade B for the 8–10th days of storage, whereas on day 11 it was graded as unfit. Acceptability scores for odor, taste and texture of cooked ungutted and gutted sea bass decreased with time of storage. Results of this study indicate that the shelf-life of whole ungutted and gutted sea bass stored in ice as determined by the overall acceptability sensory scores and microbiological data is 13 and 8 days, respectively.     

Conventional freezing plus high pressure–low temperature treatment: Physical properties,microbial quality and storage stability of beef meat

Meat high-hydrostatic pressure treatment causes severe decolouration, preventing its commercialisation due to consumer rejection. Novel procedures involving product freezing plus low-temperature pressure processing are here investigated. Room temperature (20 °C) pressurisation (650 MPa/10 min) and air blast freezing (−30 °C) are compared to air blast freezing plus high pressure at subzero temperature (−35 °C) in terms of drip loss, expressible moisture, shear force, colour, microbial quality and storage stability of fresh and salt-added beef samples (Longissimus dorsi muscle). The latter treatment induced solid water transitions among ice phases. Fresh beef high pressure treatment (650 MPa/20 °C/10 min) increased significantly expressible moisture while it decreased in pressurised (650 MPa/−35 °C/10 min) frozen beef. Salt addition reduced high pressure-induced water loss. Treatments studied did not change fresh or salt-added samples shear force. Frozen beef pressurised at low temperature showed L, a and b values after thawing close to fresh samples. However, these samples in frozen state, presented chromatic parameters similar to unfrozen beef pressurised at room temperature. Apparently, freezing protects meat against pressure colour deterioration, fresh colour being recovered after thawing. High pressure processing (20 °C or −35 °C) was very effective reducing aerobic total (2-log₁₀ cycles) and lactic acid bacteria counts (2.4-log₁₀ cycles), in fresh and salt-added samples. Frozen + pressurised beef stored at −18 °C during 45 days recovered its original colour after thawing, similarly to just-treated samples while their counts remain below detection limits during storage.     

Amount and Size of Ice Crystals in Frozen Samples as Influenced by Hydrocolloids

Measurement of the heat of fusion of frozen hydrocolloid-water solutions and of ice cream mix by differential scanning calorimetry indicated that hydrocolloids, when incorporated at a concentration of 2% (wt/wt) or less, cause only a small reduction (usually less than 3%) in the amount of ice formed. Based on the microscopic appearance of the ice cream mix, with and without gelatin, it was concluded that gelatin at a concentration of .28% (wt/wt) does not have a significant effect on: 1) the amount of ice that forms in ice cream mix, 2) the size and shape of the ice crystals existing soon after freezing, or 3) the rate at which recrystallization of ice occurs during a 2-wk period at −15 ± 2°C. It would appear likely that gelatin exerts a desirable influence on the sensory texture of frozen desserts by some mechanism other than control of ice crystal size or altering the amount of ice formed.     

Producing ice cream using a substantial amount of juice from kiwifruit with green,gold or red flesh

Ice cream prepared using a substantial amount of juice from kiwifruit with green, gold or red flesh may have consumer appeal, through the combination of kiwifruit's unique color, natural flavor and health-promoting constituents. The aqueous fractions from purees of kiwifruit with green, gold and red flesh (AFKWs) were added at 49% v/v to a basic low-fat ice cream mix that contained no commercial flavoring and coloring agents. The resultant ice creams were subjected to comparative product evaluation (e.g. overrun, melting behavior and rheological properties) and chemical analyses of bioactives (e.g. total extractable polyphenol content (TEPC), vitamin C, antioxidant capacity, polyphenol (PP) and carotenoid composition). Results revealed that both the pH pre-adjustment and pre-heating of the AFKW played critical roles in ice cream making. The ice creams retained the PP and vitamin C contents as well as natural color flavor of the kiwifruit used. The rheological properties of all ice creams showed non-Newtonian flow behavior, and the storage modulus G′ decreased in the same pattern following the order of green > gold > red. The melting rate, overrun and vitamin C content of the ice cream with green AFKW were the fastest, lowest and least, respectively. The TEPC and antioxidant capacity in the ice cream with red AFKW were the highest. The amounts of PPs and vitamin C were encouragingly high. Health beneficial compounds, dimethyl-caffeic acid hexoside, caffeic acid derivatives, protocatechuic acid, syringic acid, salicylic acid/ο-coumaric acid, lutein and beta-carotene, were detected in the final products. Thus, there are commercial possibilities for using AFKW which should be further evaluated.     

Effect of freezing under electrostatic field on selected properties of an agar gel

The objective of this study was to investigate the effects of electrostatic freezing on the quality attributes of freeze-thaw agar gel. Agar gels were frozen under static electric field 0–5.8 × 10⁴ V m^− 1 at − 20 °C. Freezing rate and energy consumption were monitored during the freezing process and microstructures of the formed ice crystals were also analyzed by light microscopy techniques. Agar gel quality changes (syneresis and texture) were evaluated after thawing the frozen samples at + 4 °C. Results showed that the energy used by a DC high voltage generator was negligibly small as compared to the energy consumption by a freezer, and the freezing rate was not significantly influenced by electrostatic freezing (ESF). ESF also reduced the size of ice crystals but did not cause obvious changes in syneresis and texture of the samples.Industrial relevanceThe effects of electrostatic field freezing on the quality attributes of agar gel have been investigated. The results showed that the electrostatic freezing can be used as a potential tool to improve the microstructure of foodstuffs during freezing.     

The growth and survival of Escherichia coli O157:H7 on minced bison and pieces of bison meat stored at 5 and 10 °C

This study investigated the growth and survival of Escherichia coli O157:H7 on minced and whole pieces of bison meat. Growth curves of native microflora, including Pseudomonas spp. and Enterobacteriaceae were also generated. A marked E. coli O157:H7 strain was inoculated onto minced and whole pieces of bison meat at an initial level of 1.5 log₁₀ cfu g⁻¹. The inoculated meat was stored at either 5 °C for 28 days or 10 °C for 21 days. Survival, but no growth, of E. coli O157:H7 was observed on both forms of bison meat stored at 5 °C, while significant growth of the organism was observed at 10 °C. E. coli O157:H7 counts on whole pieces were generally higher than counts observed on minced bison meat, and reached their highest population by 14 days, with a total increase of 3.36 log₁₀ cfu g⁻¹ on whole pieces and 2.12 log₁₀ cfu g⁻¹on minced bison meat stored at 10 °C. Under the same storage temperature, Pseudomonas spp. and total counts displayed similar growth patterns on both pieces and minced bison meat, while the Enterobacteriaceae showed a slower growth rate. This study showed that the growth of E. coli O157:H7 on bison meat is similar to that observed in studies of beef.     

Relating consumer and trained panels’ discriminative sensitivities using vanilla flavored ice cream as a medium

This research investigated the possibility of uncovering a relationship between the sensitivities of trained and consumer panels in three experiments. In Experiment I, five studies were conducted using vanilla flavored ice cream. In each study, two ice cream samples differing in formulation and/or their manufacturing process were used. They were compared by both panels using same–different tests with sureness judgments (degree of difference methodology). Using the appropriate probabilistic Thurstonian model, d′ values, a measure of the underlying sensory difference perceived between the products, were calculated and the underlying relationship between the two panels’ sensitivities uncovered. An additional study was then conducted (Experiment II). A new pair of ice creams differing in fat content was first evaluated by the trained panel. Based on the estimated d′ value (trained panel’s measured d′ = 2.69), the corresponding consumer d′ value was predicted using the relationship uncovered in Part I (consumer panel’s predicted d′ = 1.54). The same pair of ice creams was then evaluated by the consumer panel. The measured d′ value for the consumers was almost identical to that predicted by the uncovered relationship (consumer panel’s measured d′ = 1.56). Along with the discrimination component of these studies, paired preference tests were conducted (Experiment III) in order to study a link between perceived difference and expressed preference. The results give an indication of when a perceived difference might start translating into a change in acceptability of the original product. These results indicate the potential of such an approach to predict consumers’ perceptions from an in-house semi-trained or trained panel, providing a useful predictive tool and a means of reducing repetitive and costly consumer testing.     

Evaluation of biodegradable film packaging to improve the shelf-life of Boletus edulis wild edible mushrooms

The objective of this work was to evaluate the effect of poly(lactic acid) (PLA) based biodegradable film packaging combining 0.5% nisin antimicrobial polypeptide on the physicochemical and microbial quality of Boletus edulis wild edible mushrooms stored at 4 ± 1 °C. The experiment was set up by packaging mushrooms with extruded PLA films containing 0, 7.5, and 15 wt.% triethyl citrate plasticizer. The low-density polyethylene (LDPE) film was used as the control. Mushrooms stored in PLA films containing 7.5 and 15 wt.% plasticizer provided better retention of quality characteristics and received higher sensory ratings compared to mushrooms stored in pure PLA film and LDPE film. Samples with these two treatments underwent minimal changes in texture, PPO activity, total bacteria count, and sensory attributes. Results suggest that nisin in combination with plasticized PLA film has the potential to maintain B. edulis wild edible mushroom quality and extend its postharvest life to 18 days.Industrial relevanceB. edulis is one of the most commercialized mushrooms worldwide. However, as with all fresh mushrooms, there are severe preservation problems. Extruded PLA films containing triethyl citrate plasticizer plus antimicrobial agent nisin proved to be a suitable technology for mushroom conservation. This material exhibits an environmental-friendliness potential and a high versatility in food packaging.     

Histamine accumulation and histamine-forming bacteria in Indian anchovy (Stolephorus indicus)

Accumulation of histamine, trimethylamine (TMA), and total volatile base nitrogen (TVB-N), as well as microbial population incidence in Indian anchovy (Stolephorus indicus) during storage in ice and at 15 and 35 °C were investigated. Histamine was as low as 1.9 mg/100 g in 15 days at ice storage, but it increased to 19.0 mg/100 g after 32 h at 15 °C. Histamine rapidly increased to 25.4 mg/100 g when stored at 35 °C for 8 h. TVB-N and TMA began to sharply increase after 11 days in ice storage, but abruptly increased after 16 and 8 h of storage at 15 and 35 °C, respectively. A high number of Enterobacteriaceae (10¹⁰–10¹¹ cfu/g) was detected and shown to be the dominant group of microbial flora during spoilage of Indian anchovy at both 15 and 35 °C. A total of 153 bacterial strains were selected from the prescreening step using various selective media. Only 75.8% of these selected isolates showed a positive reaction in Niven's differential medium, and 27.6% of the positive isolates were true histamine formers when confirmed by the enzymatic method. Prolific histamine formers were identified as Morganella morganii, Proteus vulgaris, and Enterobacter aerogenes, and produced high histamine content of 104.1–203.0 mg/100 ml. Optimum growth and histamine production of selected strains of these three species was at 35 °C in histamine evaluation broth (HEB) containing 0.5% NaCl, pH 5. E. aerogenes produced the highest histamine of 500 mg/100 ml at the optimum condition. All studied strains did not produce histamine at ⩾10% NaCl.     

Viscoelastic properties and physicochemical characteristics of pressurized ostrich-meat emulsions containing gum additives

Minced-ostrich meat was blended and chopped with various proportions of gum powder in terms of carboxymethyl cellulose (CMC), locust bean gum (LBG) and xanthan gum (XAN) and other ingredients such as sodium chloride, sodium tripolyphosphate, linseed oil and ice. The mixed batters were then pressurized at 600 MPa and 50 °C for 40 min. Subsequently, their viscoelastic and physicochemical properties were assessed in terms of their dynamic oscillatory moduli, their resultant creep behavior, water-holding capacity and electrophoretic profiles. The results showed that the addition of individual gums and composite gum mixtures influenced both viscoelastic behavior and water-holding capacity of resulting pressurized ostrich-meat emulsions. The most elastic system (greatest G′ or smallest J₀ with 4.21 × 10^− 5 1/Pa) was the meat emulsion with 1% LBG added, while the least were those formed by adding 1% XAN or 0.5% XAN plus 0.5% CMC (J₀ with 10 × 10^− 5 and 20.3 × 10^− 5 1/Pa, respectively). Subsequent electrophoritic profiles and the measurement of the water-holding capacity of the materials suggested an evidence of ionic interaction between the basic ostrich-meat protein matrix and XAN or XAN plus CMC.Industrial relevanceOstrich meat emulsions containing composite gums were set by combined pressure and temperature. Subsequently, the pressurized gels were characterized by dynamic oscillatory, creep and other physicochemical measurements. In particular, the viscoelastic measuring system is a promising tool for ensuring quality of food biopolymers. Therefore, this methodology is relevant in the area of controlling quality or developing new products where difficulty exists in solubilising the samples.     

Antioxidant effects of Satureja montana L. essential oil on TBARS and color of mortadella-type sausages formulated with different levels of sodium nitrite

This study aimed to evaluate the effect of adding winter savory (Satureja montana L.) essential oil (EO) at concentrations of 7.80, 15.60 and 31.25 μl/g on color and lipid oxidation (TBARS) in mortadella-type sausages formulated with different sodium nitrite (NaNO₂) levels (0, 100 and 200 mg/kg) and stored at 25 °C for 30 days. The EO was extracted by hydrodistillation and analyzed by gas chromatography–mass spectrometry (GC–MS). Twenty-six chemical compounds were identified; the most prominent of which were thymol (28.99 g/100 g), p-cymene (12.00 g/100 g), linalool (11.00 g/100 g) and carvacrol (10.71 g/100 g). Among the nitrite levels tested, a concentration of 100 mg/kg of sodium nitrite appeared to be sufficient for the formation of the characteristic red color. The use of EO at concentrations exceeding 15.60 μl/g adversely affected the color of the product by reducing redness (a¹) (p ≤ 0.05) and increasing yellowness (b¹ h¹). The EO antioxidant activity was confirmed by β-carotene bleaching method and DPPH assay. Reduced values of thiobarbituric acid reactive substances (TBARS) (p ≤ 0.05) were observed in mortadellas formulated with the lowest concentrations of EO without added nitrite. This significant effect on lipid oxidation was also observed in samples containing EO and reduced amounts of sodium nitrite. The results suggest possible benefits from the combined use of EOs and minimal amounts of sodium nitrite in cured meat products.     

Determination of Ice Cream Mix Freezing Points: A Comparison of Methods

Ten batches of ice cream mix, varying in composition, were prepared. Mix freezing points were calculated by a formula method, determined by an osmometer, and the results of two methods were compared. Mix freezing points calculated by the formula method ranged from −2.36 to −3.59°C (−2.741°C mean); freezing points determined by the osmometer ranged from −2.40 to −3.53°C (−2.745°C mean). Comparative results of these methods differed by an average of .04 ± .02°C. The correlation coefficient between the two methods was .996, and there was no significant difference between them.     

Correlation between colloidal properties of ice cream mix and ice cream

Ice cream mix was produced with a range of emulsifiers and concentrations. Ice cream mix properties were measured and correlated to ice cream properties. Protein load (mg m⁻²) in ice cream mix correlated with major characteristic analyses describing the fat structure in ice cream (fat agglomerate size, fat agglomeration index, solvent extractable fat). Thus, the measurement of protein load in the mix can be used to predict ice cream fat stability and related structure with constant processing conditions. As emulsification increased, more fat could be seen at the air interface by scanning electron microscopy. High correlation coefficients were also obtained with fat structure analyses and the quantitative determination of fat in the dripped portion taken from a melting test of ice cream. Hence, fat analysis from the dripped melt fraction is suggested as a method to characterize the fat-related structure in ice cream.     

Use of microwave processing to reduce the initial contamination by Alicyclobacillus acidoterrestris in a cream of asparagus and effect of the treatment on the lipid fraction

The effects of a short-time microwave (MW) treatments on the survival of Alicyclobacillus acidoterrestris spores (10⁵ spores/g) inoculated in a cream of asparagus, along with the oxidation of the fat component (olive oil), were investigated.The samples were MW-treated at 60–100% of power (2450 MHz) for 3–7 min; power and processing time changed according to a Central Composite Design at two variables/five levels. The combinations resulting in a 2-fold reduction in the number of alicyclobacilli spores (100% of power–5 min; 80%–6 min; 80%–7 min) were stored at different temperatures and times (25 °C/27 days, 37 °C/18 days and 50 °C/9 days), to determine the decay of the qualitative characteristics of the lipid fraction. Peroxide value, K₂₃₂, K₂₇₀ and Rancimat test (induction time) were chosen as indexes of primary and secondary oxidation. MW-effect on the spores depended upon both the power and the treatment time; moreover the interaction [power] × [time] was the most significant variable. As regards the effect of MW on the lipid fraction, the results suggested that MW affected slightly induction time, peroxide values and spectrophotometric determinations, especially at low powers.Industrial relevanceSince the middle of 1990s, MW-processing has been regarded as a convenient approach for the stabilization of vegetable preserves. In Southern Italy, olive oil is an essential ingredient for this kind of food; however, it is well known that a strong thermal processing as well as not-correct storage could affect it significantly and increase the art of oxidation.This research provides some useful information on the effects of MW for a new product, an asparagus cream, focusing on the influence of this approach on olive oil oxidation, thus suggesting that MW could be a convenient preservation technique.     

The protective effect of monosodium glutamate on survival of Lactobacillus rhamnosus GG and Lactobacillus rhamnosus E-97800 (E800) strains during spray-drying and storage in trehalose-containing powders

The use of trehalose as a means of preserving Lactobacillus rhamnosus GG (LGG) and L. rhamnosus E-97800 (E800) during spray-drying and the effects of incorporated monosodium glutamate (MSG) in the carrier medium on the survival rates during drying and storage were examined. E800 was more resistant to heat than LGG in 20%, w/w, trehalose; the d-values at 65 °C were 14 s and 5.1 s, respectively. An air outlet temperature of 65–70 °C was taken as optimal for the drying process, as the resultant moisture levels in trehalose containing these bacteria were 4.1% (w/w) and 3.79% (w/w) with corresponding viable counts of 3.65 × 10⁸ cfu mL^?1 and 1.80 × 10⁹ cfu mL^?1, respectively. The presence of MSG increased the final viable counts of LGG and E800 to 3.05 × 10⁹ cfu mL^?1 and 1.30 × 10⁹ cfu mL^?1, respectively. Survival of LGG and E800 remained constant at a minimum level of ～10⁸ cfu mL^?1 during storage at 25 °C in trehalose–MSG medium.     

Enhancement of the nutritional status and quality of fresh pork sausages following the addition of linseed oil,fish oil and natural antioxidants

Fresh pork sausages (pork shoulder, pork back fat, water, rusk and seasoning) were manufactured where 15% of the pork back fat was substituted with linseed oil (LO) or fish oil (FO). Green tea catechins (GTC) and green coffee antioxidant (GCA) were added to both LO (LGTC 200 and LGCA 200) and FO (FGTC 200 and FGCA 200) substituted sausages at a level of 200 mg/kg. Raw and cooked pork sausages were either over-wrapped with oxygen permeable film (aerobic storage) or stored in modified atmosphere packages (MAP) containing 80% O₂:20% CO₂ or 70% N₂:30% CO₂, respectively for 7 days at 4 °C. Effects on fatty acid profiles, lipid oxidation, colour and sensorial properties were investigated. α-Linolenic acid increased from 1.34% (control) to 8.91% (LO) and up to 11.2% (LGTC 200 and LGCA 200). Addition of fish oil increased levels of EPA from 0.05% (control) to 2.83% (FO), 3.02% (FGTC 200) and 2.87% (FGCA 200) and DHA levels increased from 0.04% (control) to a maximum of 1.93% (FGTC 200). Lipid oxidation was low in raw and cooked linseed oil containing sausages. GTC (200 mg/kg) significantly (P < 0.05) reduced lipid oxidation in raw fish oil containing sausages after 7 days of storage. Colour parameters in raw pork sausages were unaffected by the packaging atmosphere. L¹ lightness values were lower (P < 0.05) in LGTC 200 and a¹ redness values lower (P < 0.05) in LGTC 200 and FGTC 200 after 7 days of storage. Sensory scores of cooked pork sausages were unaffected by linseed oil addition. Flavour and overall acceptability scores in cooked fish oil containing sausages were improved by GTC addition. Results obtained demonstrate potential for the production of nutritionally enhanced fresh pork sausages.