Due to the potential health hazards of synthetic antioxidants, natural products, especially natural antioxidants have been intensively examined.
Use of natural antioxidants is emerging as an effective methodology for controlling rancidity and limiting its deleterious consequences. Thus, most of the recent study has been directed towards identification of novel antioxidants from natural sources, particularly of plant origin.
This study suggested about the endogenous antioxidants in fish meat, the potential of natural antioxidants and their beneficial role for human health. How to cite this article: A. Mandal, International Journal of Meat Science, 7: DOI: Full Name:. Online First.
Current Issue. Previous Issues. Editorial Board. However TBA values did not increase significantly during that time. Evaluating how to avoid excessive oxidation in dry cured Parma hams, [ ] showed that dietary tocopherol could decrease oxidation even in hams with an increased proportion of unsaturated FA.
Also various dried fish products exist, however most work done on dried fish products deals with microbial spoilage or sensory aspects as for example in cod [ , ] and only few works also evaluate lipid oxidation. But [ ] compared different drying methods for dried milkfish Chanos chanos , a traditional Taiwanese product.
In their study cold air drying resulted in significant lower TBA values than the traditional sun drying or hot air drying. They conclude that both light and temperature were important factors which induce increased oxidation. These results agreed with [ ] who evaluated different drying methods on dried yellow corvenia Pseudosciaena manchurica and found higer oxidation in products made by the traditional sun drying process. Other works found on dried fish [ 66 , 94 ] investigated heavily salted cod, and are hence discussed in the previous section about salt.
Smoking is another traditional method to preserve meat and fish and create new products. The various techniques and the types of wood used lead to the characteristic taste of the final product [ ]. However as hot or warm smoking also includes increased temperature over a longer period and the meat parts are usually salted before smoking, also always some oxidation is initiated. In line with that effects are in general more complex, considering the various pro- and antioxidative aspects of this way of processing. For example [ 92 ] showed that smoking initially increased oxidation in chub mackerel Scomber japonicus but that it had lipid oxidation decreasing effects during storage, leading to lower TBARS values in the smoked fish compared to the unsalted non-smoked fish after 6 days.
In addition the smoke contains also substances that have been associated adverse health effects [ ]. Therefore different processing methods as for example the use of liquid smoke have been investigated. These results were ascribed to a possible higher content of phenols in the samples processed with the combined smoking procedure.
Contradictory [ ] showed that traditional smoke resulted in lower TBA values compared to the use of liquid smoke in smoked beef tongue after days storage. From an oxidation point of view, packing should be tight and compact so that the surface and oxygen access are minimized. Packaging systems and technologies have developed rapidly during the last decades [ 1 ].
Both in meat and fish the principal function is to limit bacterial spoilage and growth. In red meats also the preservation of a bright red color is important, which is an indicator of freshness for the consumers [ 7 ]. This will be reached for example by keeping a high percentage of oxygen in a modified atmosphere package MAP , while most bacteria are inhibited by an increased concentration of CO 2 at the same time. For the different types of meat and fish the perfect gas mixture differs. A good overview is given by [ ]. In fat fish due to the high oxidation risk a gas mixture without oxygen is generally recommended.
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- Recent Progress in Operator Theory: Proceedings of the XIXth International Conference on Operator Theory, Timisoara (Romania), 2002.
- Atmospheric Oxidation and Antioxidants, Volume II;
- Antioxidants in Science, Technology, Medicine and Nutrition;
Examples for the application of vacuum packing technique are given by [ ] for fish burgers and by [ 80 ] for salmon fillets. Unfortunately these studies have not investigated oxidation in normal versus vacuum packing. However [ ] investigated the effect of different storage conditions on oxidation in burgers made from rabbit meat and found decreased oxidation when vacuum packing was used. Low dose irradiation is a very effective method to kill many bacteria including Salmonella and Escherichia coli , but it is also known to generate hydroxyl radicals and could hence lead to increased oxidation in meat and fish products [ ].
However slightly higher values of malondialdehyd were found in turkey breast with the highest dose compared to the other meats at the same dose. In canned fish the major part of oxidation seemed to occur due to the heating step before and during sterilization [ , ]. The longer the storage time and the higher the storage temperature the more oxidation and lipolysis will take place and the higher the content of easily oxidable FFA will be. Beside these factors also the filling media seemed to have a significant impact [ ].
On the other hand [ ] evaluated the effect of natural antioxidants from the canning oil on canned tuna and found protective effects against lipid oxidation from extra virgin olive oil rich in phenols and also partly from soybean oil rich in tocopherols. Highest oxidation was found in tuna canned in brine in that experiment. In general the results show that even added antioxidants like spices or other plant antioxidants could have a positive effect against oxidation in canned fish products. However, to our knowledge the effect of the addition of antioxidants or the effect of spices present in the brine has not been investigated yet.
In canned meat products the situation is expected to be similar as in fish, but not as much research as on fish products concerning oxidation has been executed. This might be due to the fact that there are more canned fish products on the market and that fish is known to have higher susceptibility to oxidation due to its higher content of PUFA. However, in one of the few more recent studies [ ] investigated the importance of the raw product composition and found lowest oxidation in the product with lowest fat content. As these products often include minced or grinded meat and several other ingredients beside the raw muscle as well as they require several processing steps, all of these will have an influence on the oxidation behavior.
On the other hand this creates a great chance to add antioxidants or to optimize processing techniques and packaging towards the lowest possible oxidation status of the final product. In general it can be said that also in this case the fish products will be the ones which are more prone to oxidation due to their more unsaturated FA composition.
Atmospheric oxidation and antioxidants - Gerald Scott - Google книги
Antioxidants additives in fast food products are for example rosemary extract showing an antioxidative effect in mackerel burgers [ ] and or as a more novel ingredient yerba mate extracts, which enhanced lipid stability in beef hamburgers [ ]. But also processing methods or packaging can be used to increase oxidative stability. For instance [ ] used vacuum packing in addition with the applied antioxidants in the mackerel burgers, while [ ] evaluated a combination of irradiation and different packing environments to increase shelf life in pork patties.
Sausages are very favorite and omnipresent meat products around the world.
Oxidation and Antioxidants in Fish and Meat from Farm to Fork
A wide variety of categories such as raw, cooked, dry fermented, cooked smoked, raw smoked or precooked sausages exist. Through the addition of especially spices the oxidation in these products can efficiently be decreased [ ] for example used Spanish paprika and garlic or a mixture of nitrite, nitrate and ascorbic acid in chorizo type sausages. Adding Palatase M. On the other hand, the authors found an increased amount of volatile compounds which could indicate an increased oxidation due to the added enzyme. Antioxidants delay or inhibit the process of oxidation, even when present in low concentrations [ ].
Some antioxidants function as radical scavengers or peroxide decomposers, while others quench singlet oxygen, remove catalytic metal ions or oxygen, or inhibit enzymes. The cellular antioxidants can be classed as low molecular substances and enzymes that are either water-soluble or fat-soluble. It is well known that phenolic compounds from spices and herbs have an antioxidative potential due to their possibility to act as a radical scavengers [ , ].
A short review and a list of some polyphenols with their respective antioxidant activity can be found in [ ]. Various spices have hence been tested in a wide range of products from sausages over meatballs to fish fillets and fish oil [ , , , ]. The advantage in the use of spices and herbs is that they are natural and in case of various products often are anyway included in the spicing or that they blend in to the desired taste of the final product. Consumers appreciate having natural antioxidants in their products over synthetic ones. For example [ ] found that addition of 0.
The high antioxidant capacity of berries is particularly due to their content of different phenols, anthocyanins and ascorbic acid [ 21 ]. Besides health benefits related to their natural antioxidants, colour attributes of berries are also of interest in food processing, as colour plays a vital role to the acceptability of foods. A wide range of various fruits and berries has shown antioxidant capacity as for example cranberries, elderberries, black currant and many more [ , ].
For example, grape seed extracts were used to inhibit lipid oxidation in muscle from chicken, beef and pork [ 14 ] as well as in turkey meat [ ] and polyphenols extracted from grape pomance inhibited lipid oxidation in fish muscle [ ]. Even more unusual combinations have been tested successfully, as for example the antioxidative effect of various berry concentrates as marinades for herring fillets [ 17 ]. Other applications are cranberry juice powder as antioxidant rich feed for pigs [ 58 ], cranberry extract as additive to separated turkey and ground pork meat [ ], grape antioxidant dietary fibre in minced fish [ ] or tomatoes in beef patties.
Beside spices, herbs and fruits also teas and other possible sources for natural antioxidants have been evaluated. Among others, tea catechins have been tested and used as antioxidants in various food products. Extracted tea catechins from green tea showed significant potential to inhibit lipid oxidation in red meat, poultry and in fish muscle [ ]. Instant green tea has shown to slow down oxidation in frozen mackerel [ ]. Chitosan is the deacetylated form of chitin and has been shown to have antibacterial and antifungal properties and has therefore reached some attention as food additive [ ].
In its original form it is ineffective as antioxidant, however [ ] have shown that as a glucose complex chitosan exhibited both antimicrobial and antioxidative effects in pork salami. Besides research is constantly searching for new sources of antioxidants as for example tomato seed oil from tomato pomance industrial tomato waste [ ] or industrial onion waste [ 54 ].
These antioxidant rich waste products could be added to the animals feed as successfully shown by [ 53 ] where eggs from chicken fed tomato byproducts contained higher amounts of lycopene compared to normal eggs. Or on the other hand extracts from these byproducts could be used as additives directly to the food products as suggested by [ ].
Similarly byproducts from wine and olive oil byproducts inhibited oxidation in minced fish and frozen mackerel fillets respectively [ , ]. As a more exotic possible additive [ ] investigated antioxidant properties of Indian red seaweeds. As mentioned before, in addition to the antioxidative effect a substance has alone, there are as well always interactions that can influence the bioavailability, the antioxidative effect and mechanisms between the various nutrients.
For example vitamine C and vitamine E have been found to interact as antioxidants, tocopheroxy radicals are reduced back to tocopherols by ascorbic acid [ 32 ]. As in meat and fish products this mechanisms takes place at the border between lipid and water phase, the radical is removed from the lipid phase and the lipid oxidation process due to that radical is terminated.
Similar to the synergistic action of tocopherols and ascorbic acid, the more hydrophilic iso flavonoids and their glycosides regenerate the lipophilic carotenoids which are active as radical scavengers in the lipid phase. Furthermore carotenoids also showed to enhance antioxidant activity of vitamin E [ ]. Moreover [ ] reported that astaxanthin and tocopherol act via different mechanisms in salmon and hence improve stability against oxidation at different stages of oxidation. The use of combined added antioxidant and other preserving techniques has also shown effects as earlier presented in the case of [ 49 ] where modified atmosphere packaging was used in combination with antioxidants and where also the combination of two different antioxidants, namely rosemary and ascorbic acid gave the best results.
Furthermore [ 93 ] showed that a combination of various preservation techniques gave the best results against lipid oxidation in salted mackerel. On the other hand [ 94 ] showed that ascorbate might have pro-oxidative effects due to concentration and depending on the presence or absence of other oxidants. For instance did ascorbate concentrations below 50ppm in combination with 5 ppm copper in the brine prevented formation of TBARS while concentrations above ppm in absence of copper had pro-oxidative effects.