Kezban Candoğan

Antimicrobial activity of soy edible films incorporated with thyme and oregano essential oils on fresh ground beef patties

Antibacterial activity of soy protein edible films (SPEF) incorporated with 1, 2, 3, 4 and 5% oregano (OR) or thyme (TH) essential oils was evaluated against Escherichia coli, E. coli O157:H7, Staphylococcus aureus, Pseudomonas aeruginosa and Lactobacillus plantarum by the inhibition zone test. Effects of SPEF containing 5% OR and TH or a mixture of OR+TH (ORT) were also tested on fresh ground beef during refrigerated storage (at 4 degrees C). OR and TH incorporated SPEF exhibited similar antibacterial activity against all bacteria in inhibition zone test. While E. coli, E. coli O157:H7 and S. aureus were significantly inhibited by antimicrobial films, L. plantarum and P. aeruginosa appeared to be the more resistant bacteria. SPEF with OR, ORT, and TH did not have significant effects on total viable counts, lactic acid bacteria and Staphylococcus spp. when applied on ground beef patties whereas reductions (p<0.05) in coliform and Pseudomonas spp. counts were observed.

The effects of carrageenan and pectin on some quality characteristics of low-fat beef frankfurters.

Effects of carrageenan (0.3, 0.5, or 0.7%) and carrageenan (0.3, 0.5, or 0.7%) with a pectin gel (20%) on some quality characteristics of low-fat beef frankfurters were evaluated in comparison to a high-fat control (HFC) and a low-fat control (LFC). While low-fat frankfurters had <3.0% fat, 73-76% moisture, 13-14% protein, HFC had 17% fat, 59% moisture, and 14% protein. A reduction of 50-59% in cholesterol was determined in low fat beef frankfurters as compared to HFC (P<0.05). Better process yield and emulsion stability, and less purge were observed with increasing carrageenan concentration. Treatment groups showed higher water holding capacity (WHC) than LFC, and lower WHC than HFC (P<0.05). With increasing carrageenan concentration, WHC increased and penetrometer value decreased in low-fat frankfurters.

Storage stability of low-fat beef frankfurters formulated with carrageenan or carrageenan with pectin

Storage stability of low-fat frankfurters (<3.0 fat content) formulated with carrageenan (0.3, 0.5, and 0.7%) or carrageenan with a pectin gel (PG) (20%) was examined during 49-day refrigerated storage. Low fat frankfurters had higher bacterial growth than high-fat control (HFC) over the refrigerated storage due to higher water activity resulting from extra water addition. While there was no change in the pH of low-fat frankfurters initially due to carrageenan or PG incorporation, the most noticeable pH decline was observed in PG-added frankfurters followed by only carrageenan added ones over the storage period. HFC had the highest (P<0.05) TBA value and the lowest redness index (a(∗)/b(∗)) all the time as compared with carrageenan or carrageenan and PG added low-fat frankfurters. Low-fat frankfurters formulated with either carrageenan or carrageenan with PG had acceptable sensory scores.

Advanced retorting, microwave assisted thermal sterilization (MATS), and pressure assisted thermal sterilization (PATS) to process meat products

Conventional thermal processes have been very reliable in offering safe sterilized meat products, but some of those products are of questionable overall quality. Flavor, aroma, and texture, among other attributes, are significantly affected during such processes. To improve those quality attributes, alternative approaches to sterilizing meat and meat products have been explored in the last few years. Most of the new strategies for sterilizing meat products rely on using thermal approaches, but in a more efficient way than in conventional methods. Some of these emerging technologies have proven to be reliable and have been formally approved by regulatory agencies such as the FDA. Additional work needs to be done in order for these technologies to be fully adopted by the food industry and to optimize their use. Some of these emerging technologies for sterilizing meat include pressure assisted thermal sterilization (PATS), microwaves, and advanced retorting. This review deals with fundamental and applied aspects of these new and very promising approaches to sterilization of meat products.

Free amino acids and bioactive peptides profile of Pastırma during its processing

This study is focused on the characterization of the proteolysis occurred during the processing of Pastırma, a traditional Turkish dry-cured meat product, which is responsible for its final characteristics. Thus, the evaluation of naturally generated free amino acids and peptides present at 0, 2, 5, 10, and 21days of processing and the bioactivity of peptide fractions have been approached. Peptides were examined by MALDI-TOF and results showed differences in the amount of generated peptides at different times of processing, and a total of 29 peptides were newly generated at Day 21 in comparison with Day 2 during processing. The water soluble fraction of Pastırma at the end of the curing period (Day 21) was also analyzed by size-exclusion chromatography and some of the collected fractions demonstrated strong ACE-inhibitory and antioxidant activities. In fact, Pastırma showed an ACE inhibitory activity higher than 86% from 220 to 270mL corresponding to molecular masses between 900 and 1500Da, and also a DPPH radical-scavenging activity above 60% at 250 to 300mL corresponding to molecular masses between 700 and 2000Da. Thus, Pastırma represents a good source of natural ACE-inhibitory and antioxidant peptides which might be due to the proteolysis occurred by endogenous enzymes and the contribution of the çemen paste used in production.

High Pressure Processing in Combination with High Temperature and Other Preservation Factors

High pressure processing (HPP) has shown its efficacy in treating a number of food products of very diverse origin. For this reason, HPP has been adopted by a number of food processing companies to replace or partially replace existing preservation techniques. At the same time, HPP offers the possibility to develop new products with very attractive characteristics. Nevertheless, this novel technology has some limitations, and one way to enhance its efficacy is to combine it with others where synergistic or additive effects are attained. The most noticeable combination is what is known as pressure assisted thermal sterilization (PATS), an approach which is developing interest at the academic and industrial levels because it offers the opportunity to sterilize foods where the quality of the finished product is superior to those processed by conventional thermal treatments. HPP could also be combined with other so-called hurdles such as carbon dioxide, bacteriocins, vegetable extracts, organic acids, osmotic dehydration, pulsed electric fields, and ohmic heating, to name a few. These combinations and a few others are covered in this chapter where PATS receives the most attention.

Lipolytic Changes in Fermented Sausages Produced with Turkey Meat: Effects of Starter Culture and Heat Treatment

In this study, the effects of two different commercial starter culture mixes and processing methodologies (traditional and heat process) on the lipolytic changes of fermented sausages manufactured with turkey meat were evaluated during processing stages and storage. Free fatty acid (FFA) value increased with fermentation and during storage over 120 d in all fermented sausage groups produced with both processing methodologies (p<0.05). After drying stage, free fatty acid values of traditional style and heat processed fermented sausages were between 10.54-13.01% and 6.56-8.49%, respectively. Thiobarbituric acid (TBA) values of traditionally processed fermented sausages were between 0.220-0.450 mg·kg-1, and TBA values of heat processed fermented sausages were in a range of 0.405-0.795 mg·kg-1. Oleic and linoleic acids were predominant fatty acids in all fermented sausages. It was seen that fermented sausage groups produced with starter culture had lower TBA and FFA values in comparison with the control groups, and heat application inhibited the lipase enzyme activity and had an improving effect on lipid oxidation. As a result of these effects, heat processed fermented sausages had lower FFA and higher TBA values than the traditionally processed groups.

Nonthermal Stabilization Processes

The processing of food by nonthermal technologies—such as high pressure, pulsed electric fields, and ultrasound—is gaining relevance within the food industry. Fresh-tasting foods along with minimal impact on nutritional attributes, low energy consumption, minimal and fast processing, environmental-friendliness, effectiveness at inactivating pathogenic and spoilage microorganisms some of the characteristics making these technologies so attractive. This chapter focuses on the affect of selected nonthermal-processing technologies on the stability of bioactive compounds in a number of foods. A brief description of these technologies is also included.