Microwave applications in the food industry: an overview of recent developments.

Microwave radiation has the ability to heat a material with dielectric properties. Material absorbs microwave energy and then converts it into heat, which gives the possibility of a wide use of microwaves in many industry sectors or agricultural sciences. Microwaves are especially widely used in food industry. The main objective of this paper is to present an overview of recent development regarding microwave applications in food industry. Many techniques in food processing (pasteurization, sterilization, drying, thawing, blanching and stunning) are assisted by microwave energy. It should be mentioned also the use of microwaves in nutrients and nutraceuticals production. Waste generation is an integral part of food production. Microwaves have also application in wastes management. The results of experiments, factors affecting heating and their practical application have been discussed. Many cases have been compared with conventional process methods. The use of microwaves shows many advantages. The most important aspect is shortening the time of the thermal process (even by 50%) and reducing the costs of the operation. In addition, it allows to increase the efficiency of processes while maintaining high quality. The examples of microwave applications given in the article are environmentally- friendly because the conditions of thermal processing allow for reducing the use of solvents and the amount of sewage by decreasing the demand for water. It is anticipated that microwaves will become increasingly popular, with the development of new microwave technologies solving many problems in the future.

Physicochemical Properties, Fatty Acid Composition, Volatile Compounds of Blueberries, Cranberries, Raspberries, and Cuckooflower Seeds Obtained Using Sonication Method.

Every year, thousands of tons of fruit seeds are discarded as agro-industrial by-products around the world. Fruit seeds are an excellent source of oils, monounsaturated fatty acids, and n-6 and n-3 polyunsaturated essential fatty acids. This study aimed to develop a novel technology for extracting active substances from selected seeds that were obtained after pressing fruit juices. The proposed technology involved sonification with the use of ethyl alcohol at a low extraction temperature. Seeds of four species-blueberry (Vaccinium myrtillus L.), raspberry (Rubus idaeus), cranberry (Vaccinium macrocarpon), and cuckooflower (Cardamine pratensis)-were used for extraction. Following alcohol evaporation under nitrogen, the antioxidant activity, chemical composition, and volatile compounds of the obtained extracts were analyzed using chromatographic methods, including gas chromatography (GC)-mass spectrometry (MS) (GC-MS/MS), and high-performance liquid chromatography-MS. We analyzed physicochemical properties, fatty acid, and volatile compounds composition, sterol and tocochromanol content of blueberry, cranberry, raspberry, and cuckooflower seed oils obtained by sonication. This method is safe and effective, and allows for obtaining valuable oils from the seeds.

Biochemical Properties Affecting the Nutritional Quality, Safety, and Aroma of Dry-Cured Products Manufactured from Meat of Rare Native Pig Breeds.

The aim of study was to compare the biochemical properties affecting the nutritional quality, safety, and aroma of dry-cured products manufactured from valuable meat of rare native pig breeds: Pulawska (Pul) and Zlotnicka Spotted (ZS). The count of lactic acid bacteria (4.4 log cfu/g) and the release of palmitic (23.1% and 25.9%), oleic (44.1% and 42.2%), and linoleic acids (8.3% and 7.8%), as well as arginine (30.0 and 44.3 mg/kg), histidine (25.8 and 20.6 mg/kg), and lysine (26.8-22.9 mg/kg), shaped the final pH (5.3 and 5.4) in Pul and ZS products during the 4 week maturing, respectively. Lastly, Pul and ZS meat differed in the proportion of decanoic, lauric, stearic, arachidic, and conjugated linoleic acids. The high content of putrescine (23.7 mg/kg), cadaverine (54.3 mg/kg), and tyramine (57.2 mg/kg), as well as a twofold greater share of histamine (163.2 mg/kg) and tryptamine (9.1 mg/kg), indicated a more advanced decarboxylation of ZS meat. Volatile compounds differentiating Pul and ZS meat were primarily hexanal, 3-hydroxybutan-2-one, phenylacetalaldehyde, 2,3-dimethyl-2-cyclopenten-1-one, 2-cyclopenten-1-one, and 3-methyl- and 2-cyclopenten-1-one. Most marked volatile compounds were obtained as a result of microbial activity (acetic acid, 3-methylbutan-1-ol, ethanol, acetone, and 3-hydroxybutan-2-one), advanced lipid oxidation, and decomposition of secondary oxidation products (hexanal, phenylacetaldehyde, and 2-cyclopenten-1-one).

Meat Quality of the Native Carpathian Goat Breed in Comparison with the Saanen Breed.

Goats provide valuable products that are appreciated by consumers who are looking for food that is not only tasty but also healthy, and, probably, one of them is goat meat. Breeding of local breeds such as the native Carpathian goat has been gaining importance in recent years, which creates an opportunity for the development of the goat meat market. The aim of this study was to investigate the influence of goat breed on the basic chemical, fatty and amino acid composition, colour and sensory evaluation of meat. The research material consisted of Carpathian goats from the NRIAP experimental plant located in the southern part of Poland, and goats from a farm keeping Saanen goats in south-eastern Poland. Ten male goat kids from each breed were taken to the NRIAP farm. The quality of meat obtained from the leg (m. biceps femoris) of male goat kids about 150 days old at slaughter was analysed. The meat of the Carpathian goat was characterised by a lower content of protein and cholesterol (p < 0.01), and a higher content of fat and general collagen compared to the meat from Saanen goats (p < 0.05). Cholesterol content in goat meat of both breeds was similar and ranged from 55.08 mg/100 g (Carpathian) to 56.79 mg/100 g (Saanen). Despite the higher collagen content, the goat meat of Carpathian breeds was characterised by lower shear force, less hardness (p < 0.05) and chewiness, being a more delicate meat. The fat of Carpathian goat breeds was characterised by a higher content of monounsaturated acids, mainly C 18:1n:9, and a more favourable (lower) saturation index, S/P (p < 0.05). The meat of Carpathian goats was characterised by a higher health-promoting quality compared to the meat from Saanen goats. In the goat meat of both breeds, there were no differences between the total content of exogenous and endogenous amino acids. The essential/nonessential amino acids (EAA/NEAA) ratio in the meat of the analysed breeds was 0.88:0.89. However, the meat of the Carpathian goats was statistically significantly higher concerning the content of phenylalanine, histidine, proline, alanine and tyrosine, as compared to the meat of the Saanen goats. The obtained results confirm the high quality of the meat of the local Carpathian breed in comparison to the Saanen breed.

Nutritional value and organoleptic assessment of traditionally smoked cheeses made from goat, sheep and cow's milk.

The use of small ruminant milk for smoked cheese production makes it possible to incorporate valuable nutrients into the diet, especially as the consumption of unprocessed sheep or goat's milk is low compared to that from cows. Smoking of food not only prolongs its shelf-life but also improves its flavour. Taking the fact that many consumers do not accept some organoleptic properties of milk from small ruminants into account, the aim of the study was to assess and compare the organoleptic and nutritional properties of traditionally smoked cheeses made from goat, sheep and cow's milk. The analysed cheeses differed in terms of dry matter content and its components such as protein and fat. Their acidity was comparable, except for the sample made of raw goat's milk, which was characterised by a relatively high pH value (6.12 ± 0.06). The highest content of CLA (2.30 ± 0.04%), as well as the highest share of unsaturated and polyunsaturated fatty acids, was determined in the cheese made from sheep's milk. Moreover, the content of butyric and caproic free fatty acids in cheeses made from goat's milk was found to be several times higher than in the other analysed cheeses. The organoleptic assessment did not reveal any significant differences between the cheeses produced at small, private farms and in industrial conditions, or between different types of cheese, regardless of the type of milk from which they were produced.

Key Aroma Compounds in Roasted White Koluda Goose.

Aroma-active compounds in the roasted leg meat of White Koluda goose were assayed by gas chromatography-olfactometry, using aroma extract dilution analysis and solvent-assisted flavor evaporation. Quantitation, recombination-omission tests, and sensory evaluation were carried out. Thirty aroma compounds, for which odor activity values (OAVs) were calculated and for which the flavor dilution factors were greater than or equal to 1, were identified. The concentration of aroma compounds ranged from 0.06 to 633 (µg/kg). The highest OAVs (>1024) were for 2-furfurylthiol, 2-acetyl-1-pyrroline, and 1-octen-3-one. Nine key aroma compounds were: 2-furfurylthiol, 2-acetyl-2-thiazoline, 1-octen-3-one, 2-phenylethanethiol, 4,5-dimethyl-3-hydroxy-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E,E)-2,4-decadienal, 2-acetyl-1-pyrroline, and 3-(methylthio)propanal. The intensity of the dominating roasted, meaty/broth, and fatty notes in the recombination model consisting of the key odorants were rated (10-point scale) at 4.6-5.8 points, relative to the original roasted goose (5.2-6.2). The aroma compounds defined predominantly the meaty, roasted, and fatty flavors during the descriptive sensory evaluation of the roasted goose meat.

Protocol for Designing New Functional Food with the Addition of Food Industry By-Products, Using Design Thinking Techniques-A Case Study of a Snack with Antioxidant Properties for Physically Active People.

The aim of the work was to develop an easy-to-follow protocol for designing novel functional products with the addition of food industry by-products using design thinking techniques. As a result, a 12-step protocol has been designed and presented. The protocol consists of steps from the initial formation of the design team, through all the stages of the production and prototyping, until establishing the final storage conditions and creating final documentation. The protocol has been validated and explained using a case study in which a fish industry by-product hydrolysate with bioactive properties was used to develop a novel functional food product for physically active people: a date bar with carp meat and carp skin gelatin hydrolysate. Following the 12 steps presented in the protocol resulted in developing a food product with high nutritional value and antioxidant power which remains stable during storage at reduced temperatures. Moreover, the product is characterized by good sensory qualities and can be easily implemented into full-scale production. The newly designed protocol is an easy-to-follow method that could be used in almost any kind of food industry sector to sucesfully develop user-focused functional food products with by-product addition.

The Quality and Health-Promoting Value of Meat from Pigs of the Native Breed as the Effect of Extensive Feeding with Acorns.

The popularity of meat from animals of native breeds is growing all over the world, due to consumer belief regarding its higher quality compared to meat from industrial farm animals. In addition, the living conditions (welfare) are of great importance for consumers. We observed the effect of different ways of keeping and feeding pigs of the same conservative breed on the quality of meat and its health benefits. The aim of the study was to compare the meat quality from pigs of the native Zlotnicka Spotted breed, fattened intensively or extensively (with conventional farm-produced compound feed and acorns). The meat from free-range pigs extensively fed on silage and small amounts of acorns was characterized by a higher content of fat, which acts as a carrier for flavor and juiciness, as well as higher monounsaturated fatty acid (MUFA) content (p ≤ 0.05) and lower atherogenic, thrombogenic, and peroxidability indices (p ≤ 0.05). It may be stated that the meat quality of the native pig breed is significantly dependent on the housing and feeding method. A more beneficial effect on the quality of meat and its dietetic value, as well as its susceptibility to rancidity, can be obtained throughextensive pig feeding with roughage and the addition of acorns.

Mutations in Leptin (LEP) Gene Are Associated with Carcass and Meat Quality Traits in Crossbreed Rabbits.

Leptin is a hormone synthesized and secreted primarily in adipose cells that help to regulate energy balance. This study examined the associations of single nucleotide polymorphisms in the rabbit leptin gene with growth traits, slaughter traits and physicochemical parameters of New Zealand White (NZW) and Belgian Giant Grey (BGG) crossbreed rabbits. In total, 320 crossbreed animals were genotyped for polymorphisms within exon 2-g.16081633T>C, intron 1_2-g.16081420C>T, and within UTR-g.16079636C>G for association analysis. Identified polymorphisms within rabbits leptin gene showed significant differences for dissectible fat percentage in carcass and dissectible fat weight in intermediate part (g.16081633T>C). Moreover, meat traits like protein content (g.16081633T>C; g.16079636C>G), intramuscular fat content (g.16081633T>C; g.16079636C>G, g.16081420C>T), dry matter (g.16081420C>T), ash (g.16081420C>T), water (g.16081420C>T), and cohesiveness (g.16081420C>T, g.16079636C>G) were affected by polymorphisms in leptin gene. We conclude that polymorphism in the rabbit leptin gene influences important carcass and meat traits of NZW × BGG crossbreeds. Therefore, polymorphisms identified in this study may be used in selection as a meat trait markers.

The effect of dietary supplementation with dried fruit and vegetable pomaces on production parameters and meat quality in fattening pigs.

The presence of biologically active substances in feed mixture is discussed to have beneficial effect on animals' health and products. The purpose of the study was to determine the effect of dietary supplementation with dried apple, chokeberry, black currant, strawberry and carrot pomaces on production parameters and meat quality in fattening pigs. The use of dried pomaces of chokeberry showed tendencies for increased feed intake and reduced fattening period. The dried pomaces had no impact on saturated and monounsaturated fatty acids profile in meat, however in some groups an elevated level of polyunsaturated fatty acids from n-3 family and a decline in total cholesterol level was observed (P≤0.05). The highest oxidative stability and vitamin E content was found after supplementation with black currant (P≤0.05). Summarizing, the used dried pomaces improved several parameters related to meat quality, what might positively influence consumers' health.

The effect of hyaluronic acid addition on the properties of smoked homogenised sausages.

BACKGROUND: This research studied the possibility of using hyaluronic acid (HA) as a food additive for meat emulsions to create a novel functional food with improved rheological and water binding properties. Sausages with 200 and 500 g kg-1 water addition were supplemented with 0, 0.01, 0.05 and 0.1 g kg-1 of HA and stored for 14 days in vacuum. Rheology, texture, weight losses, proximate composition and microbiological analyses were performed together with the sensory evaluation of produced sausages. RESULTS: Surprisingly, the results show that the addition of 0.05 and 0.1 g kg-1 HA reduced yield and the stability of meat emulsion by causing water outflow from the product and decreased the sensory scores of the produced sausages. The sausage with 500 g kg-1 water and 0.01 g kg-1 HA addition was the only economically viable option for introducing the product on the market. CONCLUSION: HA has a potential of being a perfect functional food additive for meat industry, although further research regarding processing conditions should be performed. © 2016 Society of Chemical Industry.

Increasing meat product functionality by the addition of milled flaxseed Linum usitatissimum.

BACKGROUND: Functional meat products are still rare on the market because it is difficult to incorporate new ingredients and obtain both a healthy and acceptable product. Flaxseed is known for its beneficial properties and, in the present study, it was used as an ingredient in the production of homogenised and liver sausages (0%, 5% and 10% flaxseed addition). RESULTS: Homogenised and liver sausages with the addition of 5% flaxseed were given the highest scores by the consumers, although the colour changed with the addition of flaxseed. The spreadability and hardness of the liver sausages increased with the addition of flaxseed, whereas the texture of homogenised sausages did not change. Addition of flaxseed improved the fatty acids profile from a health point of view for both products, as a result of increasing n-3 fatty acids and overall polyunsaturated fatty acids content. Values for thiobarbituric acid reactive substances were higher in products with flaxseed and were observed to increase during storage. CONCLUSION: The results of the present study indicate that it is possible to obtain products that are acceptable by consumers and, at the same time, are more healthy. A high level of α-linolenic acid in the sausages at a level of addition of 5% allows the product to be labelled with information regarding their high omega-3 fatty acid content. However, those products are more susceptible to oxidation. © 2016 Society of Chemical Industry.

Microbiological and chemical safety concerns regarding frozen fillets obtained from Pangasius sutchi and Nile tilapia exported to European countries.

BACKGROUND: Microbiological and chemical safety concerns regarding frozen fillets from pangasius catfish (Pangasius hypophthalmus) exported to Poland, Germany and Ukraine and Nile tilapia (Oreochromis niloticus) exported to Poland and Germany were investigated by analyzing heavy metal residues, microbiological hazards, biogenic amines, and thiobarbituric acid (TBA) and total volatile basic nitrogen (TVB-N) content. RESULTS: The heavy metal residues from all studied samples were far lower than the limits established by authorities. The most abundant biogenic amine found was histamine, with a maximum content of 9.6 mg 100 g(-1) , found in pangasius exported to Poland. The total viable counts were from 2.8 log cfu g(-1) in pangasius exported to Ukraine to 4.3 log cfu g(-1) in pangasius exported to Germany. Vibrio spp. were present in 70-80% of all studied pangasius groups, whereas there no Vibrio spp. were found in the studied tilapia samples. 30% of Pangasius fillets exported to Poland were contaminated with coagulase-positive staphylococci. No E. coli was found in any of the studied samples. Although the results of TBA analysis differed significantly between studied groups, the malonic aldehyde content in all studied groups was still very low. The TVB-N content in frozen fillets from pangasius was significantly lower than in frozen tilapia fillets. CONCLUSIONS: We reported that pangasius catfish frozen fillets were widely contaminated with Vibrio spp., which could prove hazardous for the final consumer if the fish is eaten raw or undercooked. The rest of the analysis showed no other reason for concern associated with Nile tilapia and Pangasius catfish frozen fillet consumption.

The quality of carp (Cyprinus carpio L.) cultured in various Polish regions.

BACKGROUND: Although environmental factors greatly affect the quality of carp meat, no regulations impose labelling the place of cultivation of freshwater fish. That is why the purpose of this study was to determine the quality of carp meat cultivated in several regions of Poland as well as to assess the necessity of implementing such regulations. RESULTS: The influence of the cultivation region on colour, nutrition value, health safety and sensory quality of carp meat was assessed. The analysis included colour measurement, determination of fatty acid profile and sensory evaluation of carp muscle. Moreover, microbiological analysis of the fish surface was performed. The results show that the place of cultivation does not influence the lightness (L*) of fillet, but has an impact on other colour parameters (a*, b*). The microbiological quality of fish from all studied farms was satisfactory, since no pathogenic microorganisms were observed on the fish surface. The fatty acid profile was fairly varied (P < 0.01), depending on the place of cultivation. CONCLUSION: Since final results seem ambiguous, further analyses of quality features of carp from various regions and cultures should be performed, before any recommendation for the necessity of labelling the place and method of cultivation should be suggested.

Effect of bioactive substances found in rapeseed, raspberry and strawberry seed oils on blood lipid profile and selected parameters of oxidative status in rats.

Rapeseed, strawberry and raspberry seed oils are a rich source of polyunsaturated fatty acids and antioxidants such as tocols, bioflavonoids and phytosterols. The aim of the study was to determine changes in the blood lipid profile of rats fed with rapeseed, strawberry and raspberry seed oils and their effects on selected parameters of oxidative status. The experiment was carried out on male Wistar rats. The oils were administered by oral gavage for 5 weeks once daily at the dose of about 0.8 ml per rat. Blood samples were taken before and after supplementation period. The activity of superoxide dismutase (SOD) and glutathione peroxidase (cGPx) was assessed in erythrocytes and contents of triglycerides (TG), total cholesterol, low-density fraction of cholesterol (LDL) and high-density fraction of cholesterol (HDL) were assessed in plasma. The experiment shows that oils supplemented in the diet for 5 weeks had no significant effect on the level of triglyceride (TG), total cholesterol as well as HDL and LDL fractions. Reduced activity of cGPX and SOD in the group of rats receiving raspberry and strawberry seed oils suggests that these native oils may contribute to oxidative stability (improves antioxidant status). Thus, strawberry and raspberry seed oils can be considered as special biological oils, which constitute potential nutraceuticals reducing oxidative stress.

Carcass, meat quality and histochemical traits of m. longissimus lumborum from Zlotnicka Spotted pigs and commercial pigs.

Carcass, meat quality and muscle fibre traits of m. longissimus lumborum were studied in 61 Zlotnicka Spotted (ZS) pigs and 35 commercial crossbred (Polish Large White x Polish Landrace) pigs. The animals received organic feed ad libitum and were slaughtered at 210 days of age. The current findings indicate that both slaughter weight and cold carcass weight were significantly lower, and backfat thickness higher for ZS pigs compared to commercial pigs, while the commercial pigs exhibited longer carcasses and greater area, height and width of the loin eye. No significant differences were found in IMF content between the analysed groups. Moreover, the percentage of type I fibres was higher and their diameter was larger in m. longissimus lumborum of ZS compared to commercial pigs, whereas the opposite occurred for type IIB fibre percentage and diameter, and that concurred with markedly higher pigment content and higher pH(u), redness (a*), plasticity values, and significantly lower drip loss, WHC--loose water, and colour lightness (L*) values in ZS pigs than those found in commercial pigs. Also, sensory assessment of raw meat confirmed that m. longissimus lumborum of ZS pigs was characterized by more favourable colour and less exudative meat.

The effect of dietary CLA supplementation on meat and eating quality, and the histochemical profile of the m. longissimus dorsi from stress susceptible fatteners slaughtered at heavier weights.

The influence of adding 2% CLA to the morning feed of a group of 20 crossbred fatteners from 70 to 130 kg on meat quality, eating quality and dietetic value of m. longissimus dorsi was evaluated compared with a group of 20 controls. Addition of 2% CLA in feed did not influence fattening and slaughter results and also some traits of meat and eating quality. The only significant differences were observed in dry matter content, in meat flavour and L(∗), b(∗), and hue angle value. Meat from fatteners from the experimental group had a statistically significant higher content of CLA (P⩽0.01) and lower content of unsaturated fatty acids especially C18: 2, C18: 1 and C20: 4, PUFA fatty acids (P⩽0.01) and a reduction in the ratio of n-6: n-3 PUFA (P⩽0.01). No statistically significant influence of CLA on the content of cholesterol was observed. The results of the current histochemical study showed that dietary CLA supplementation significantly increased both the number and diameter of white fibres, and correspondingly reduced the number and diameter of red fibres. The percentage and diameter of intermediate fibres was unaffected by CLA.