Typical Defects of Natural Phospholipid Fatliquors in Leather Industry and Their Solutions

Leather made with soybean phospholipid fatliquors is prone to problems such as yellowing, elevated hexavalent chromium content, and undesirable odor. In this study, the aforementioned typical defects of soybean phospholipid fatliquors were investigated in respect to the main components, the antioxidants and the unsaturation degree of the natural soybean phospholipid. The results showed that the oxidation of soybean phospholipid is the primary source for its yellowing, elevated hexavalent chromium content, and undesirable odor. The volatile aldehydes produced by lipid oxidative rancidity are the main components of the undesirable odor. The purification of natural soybean phospholipid through removing the non-phospholipid components cannot solve the problems caused by oxidation of phospholipid. Furthermore, as a typical natural antioxidant existing in natural soybean phospholipid, tocopherols can restrain the oxidation of phospholipid to a certain degree, however, the dissolving out and destruction of tocopherols at high temperature in the phospholipid purification process can lead to more obviously oxidation of phospholipids. Additionally, the oxidation defects of phospholipid cannot be completely resolved by adding extra tocopherols, even at high dosages. The research finds that the defects of soybean phospholipid fatliquors can be thoroughly solved by increasing the saturation degree of lipid through addition reaction, the suggested iodine value of phospholipid products is lower than 20 g I2/100 g.

Antioxidant capacity of pitcher (Nepenthes) extract on oxidative rancidity of sun-dried squid

Consumers demand new biologically natural-active ingredients with a great capacity to promote a healthier advantage and free from toxicity. Pitcher (Nepenthes) is one of the naturally carnivorous climber herbs. Extract from Nepenthes plant contains numerous beneficial bioactivity characteristics. This research compared the impact of 0.05% pitcher extract demonstrated with 10 ppm butylated hydroxyanisole on the accumulation of acid value, peroxide value, carbonyl value and thiobarbituric acid during 12 months of storage. Results showed that there was no significant difference between 0.05% pitcher extract and 10 ppm butylated hydroxyanisole in respect of acid value, peroxide value, carbonyl value and thiobarbituric acid during preservation of the dried squid. Pitcher extract would be a promising alternative to replace synthetic antioxidants to overcome oxidative rancidity in the dried seafood.

Effect of Agar/AgNP Composite Film Packaging on Refrigerated Beef Loin Quality

Fresh beef loin was packaged with 0–2% silver nanoparticles (AgNPs) incorporated agar films to investigate the effect of antimicrobial packaging on meat quality changes in terms of microbiological and physicochemical properties. Raw beef cuts were directly inoculated with Listeria monocytogenes and Escherichia coli O157:H7 and stored in the air-sealed packages combined with the agar films at 5 °C for 15 days. Beef samples showed low susceptibility to the agar/AgNP composite films, resulting in about one log reduction of the inoculated pathogenic bacteria in viable cell count during storage. However, the composite films could partly prevent beef samples from directly contacting oxygen, maintaining the meat color and retarding oxidative rancidity. Experimental results suggested that the AgNP-incorporated agar films can potentially be applied in packaged raw meats as an active food packaging material to inhibit microbial and physicochemical quality deterioration during distribution and sale.

Kinetic And Oxidative Stability Of Oil-In-Water Emulsions Prepared With Denatured Soy Whey Protiens And Soy Soluble Polysaccharides

With increasing consumer awareness and growing demand for healthier processed food options, there is an ever-present push for the incorporation of nourishing ingredients into foods. Many health-promoting ingredients, for example Omega-3 fats, are prone to rancidity and are insoluble in water. A current challenge facing the Ontario agri-food sector is the addition of such ingredients that can normally be added to fatty foods, but not into water-based foods such as many store-bought beverages. Furthermore, oils such as flaxseed oil are also very sensitive to oxidation when in the presence of light, heat or air, resulting in the formation of undesirable odours and flavours as well as loss in nutritional properties. The use of food emulsions is considered an attractive approach to preserve their healthfulness while minimizing rancidity. The overall goal of the present thesis was to incorporate soybean or flaxseed oil as micron-sized droplets within water-continuous emulsions using biopolymers derived from soy industrial processing waste to help ‘protect’ the oil from visual phase separation and coalescence as well as oxidative rancidity. To meet the goal, an extraction protocol to purify and concentrate the soy whey proteins (SWP) was initially developed. This was followed by establishing a method to increase the surface activity of the SWP via denaturation (dSWP). Subsequently, emulsions consisting of soybean oil or flaxseed oil prepared with dSWP and commercially-available soy soluble polysaccharides (SSPS) were analyzed for their kinetic and oxidative stability. Results clearly showed that the combination of dSWP and SSPS could: i) kinetically stabilize model oil-in-water emulsions against coalescence and phase separation more so than dSWP or SSPS alone and ii) effectively protect emulsions containing flaxseed oil from oxidative rancidity to a greater extent than a commonly-used emulsifier (polysorbate 20). Overall, this thesis yielded a novel method to emulsify and protect polyunsaturated oils using soy-based proteins and polysaccharides. The outcomes of this study offer the attractive potential of using soy-based ingredients from industrial waste in value-added food products such as beverage-type emulsions. Findings from this study may be applied to non-food products where there is a need for the development and stabilization of emulsions (e.g., pharmaceutical, cosmetics).

Kinetic And Oxidative Stability Of Oil-In-Water Emulsions Prepared With Denatured Soy Whey Protiens And Soy Soluble Polysaccharides

With increasing consumer awareness and growing demand for healthier processed food options, there is an ever-present push for the incorporation of nourishing ingredients into foods. Many health-promoting ingredients, for example Omega-3 fats, are prone to rancidity and are insoluble in water. A current challenge facing the Ontario agri-food sector is the addition of such ingredients that can normally be added to fatty foods, but not into water-based foods such as many store-bought beverages. Furthermore, oils such as flaxseed oil are also very sensitive to oxidation when in the presence of light, heat or air, resulting in the formation of undesirable odours and flavours as well as loss in nutritional properties. The use of food emulsions is considered an attractive approach to preserve their healthfulness while minimizing rancidity. The overall goal of the present thesis was to incorporate soybean or flaxseed oil as micron-sized droplets within water-continuous emulsions using biopolymers derived from soy industrial processing waste to help ‘protect’ the oil from visual phase separation and coalescence as well as oxidative rancidity. To meet the goal, an extraction protocol to purify and concentrate the soy whey proteins (SWP) was initially developed. This was followed by establishing a method to increase the surface activity of the SWP via denaturation (dSWP). Subsequently, emulsions consisting of soybean oil or flaxseed oil prepared with dSWP and commercially-available soy soluble polysaccharides (SSPS) were analyzed for their kinetic and oxidative stability. Results clearly showed that the combination of dSWP and SSPS could: i) kinetically stabilize model oil-in-water emulsions against coalescence and phase separation more so than dSWP or SSPS alone and ii) effectively protect emulsions containing flaxseed oil from oxidative rancidity to a greater extent than a commonly-used emulsifier (polysorbate 20). Overall, this thesis yielded a novel method to emulsify and protect polyunsaturated oils using soy-based proteins and polysaccharides. The outcomes of this study offer the attractive potential of using soy-based ingredients from industrial waste in value-added food products such as beverage-type emulsions. Findings from this study may be applied to non-food products where there is a need for the development and stabilization of emulsions (e.g., pharmaceutical, cosmetics).

Ethanolic Extracts from Agro-Industrial Co-Products Enhance Oxidative Stability of Candelilla Wax or Celluloses Derivatives Oleogels

Ethanol oleoresins obtained from orange peel, pea pod, or pomegranate peel were employed to enrich soybean oil before elaborating two types of oleogels, one made with candelilla wax, another made with a mixture of celluloses derivatives, in order to determine their effect on oleogel oxidative stability. Orange peel oleoresin obtained a higher amount of polyphenols as catechol acid equivalent (9.09 meq/g), as compared to pea pod oleoresin or pomegranate peel (8.80 and 8.55, respectively), although pomegranate peel presented the higher TEAC (1.67, twice than the other samples). Oleogels elaborated with celluloses were presented better oxidative stability (oxidative rancidity and peroxide index) as compared to samples elaborated with candelilla wax, since waxes minor constituents employed as oleogelators could promote prooxidant activity. Samples with pomegranate oleoresin presented enhanced oxidative stability. Candelilla wax has a more marked effect on the oleogels thermal properties of due to their influence on fatty acids crystallization, because in celluloses oleogels the mechanism of gelation does not imply the formation of a highly ordered secondary structure. This finding opens the possibility to, on one hand, use oleoresins to enhance the oxidative stability of oleogels; and on the other hand, to select the oleogelator, waxes, or celluloses, based on thermal properties and other aspects, depending on the further application of oleogel thinking in oleogel thermoreversible capacity.

Why does lipid oxidation in foods continue to be such a challenge?

Lipid reactions are extremely complex because they involve numerous prooxidants, antioxidants, and lipid substrates whose reactivity is impacted by the physical properties of complex food systems. Understanding the interactions between the factors impacting lipid oxidation reactions is key to developing novel antioxidant strategies. Synergistic antioxidant combinations represent a promising approach to decreasing oxidative rancidity if how and where they work can be better understood.

Reducing Meat Perishability through Pullulan Active Packaging

The provision of safe products from the meat industry has been considered as the major source of protein for maintaining human health. Meat-borne outbreaks are mainly due to Salmonella typhimurium (S. typhimurium), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Clostridium perfringens (C. perfringens), reducing the shelf life and consumer demands. A variety of vulnerable substances, including cholesterol oxidation products (COPs), are generated by the oxidation of meat induced by the microbial infestations. The use of certain biodegradable active packaging, including pullulan active packaging, is being focused by the meat industry due to their safety, stability, and negligible health risks. The potential of pullulan active packaging, incorporated with silver nanoparticles and essential oils, against E. coli, S. typhimurium, Mycoplasma, and other bacterial species is exclusive. Similarly, maintenance of organoleptic properties of meat with nominal oxidative rancidity and limited human health issues can be acquired by pullulan active packaging.