Enzymatically Treated Spent Cellulose Sausage Casings as an Ingredient in Beef Emulsion Systems

The objective of this research was to incorporate an ingredient obtained from spent cellulose casings in beef emulsion modeling systems. The test ingredient (residual sausage casing [RSC]) was procured from cellulose sausage casings following thermal processing of the sausages. The casings were cleaned of contaminants before a combination of enzymatic hydrolysis and high-speed homogenization was conducted in an effort to improve the functional attributes of the cellulose casing residue (i.e., recycling/upcycling of the spent casings). The beef emulsion modeling systems used in this study consisted of 57.30% beef, 20% water, 15% olive oil, 6% of the combination of RSC and an all-purpose binder, 1.45% NaCl, 0.40% sodium tri-polyphosphate, 0.15% sodium nitrite cure, and 0.0035% sodium erythorbate. The overlying goal was to test the ability of the RSC ingredient as a partial or full replacement of binder ingredients in a beef emulsion system. Therefore, the beef emulsion model systems were prepared with 5 different levels of the RSC ingredient (0% RSC, 25% RSC, 50% RSC, 75% RSC, and 100% RSC). This study was independently replicated in its entirety 3 times (n = 3) in a completely randomized design, and data were analyzed using a generalized linear mixed statistical model. Emulsion samples were tested for proximate composition, cooking loss, emulsion stability, texture profile analysis, and instrumental color. Overall, technological properties and emulsion stability were lost as the level of the RSC ingredient increased, but low levels of the RSC ingredient (25% RSC) may help maintain acceptable levels of yield and emulsion stability while improving the sustainability of the sausage production system

Effects of grind size, temperature, and brewing ratio on immersion cold brewed and French press hot brewed coffees

This study investigated the effects of coffee ground particle size (282–1057 µm volume-weighted mean particle diameter), extraction temperature (4–37 °C), steeping time (5 min to 18 h), and brew ratio (1:3–1:11 ground:water, w/w) on the physicochemical properties of coffee brews prepared using an immersion cold brewing method. The results showed that the extraction rate and yield increased with increasing brewing temperature and decreasing grind size. Brew ratio significantly affected the extraction yield and titratable acidity of the brews, but not the extraction rate. The ratio between the absorbance at 420 nm and total dissolved solid increased with increasing brewing time, suggesting that non-enzymatic browning reactions might have occurred during the extraction process. Strong positive correlations of total dissolved solids with brew physicochemical properties (total phenol content, caffein content, titratable acidity, absorbance at 420 nm) were observed. Compared with hot brew, the cold brew coffees had significantly higher pH (5.18 vs 5.38) and surface tension (61.6 vs 64.5 mN/s) values, but lower titratable acidity (0.97 vs 0.86 g/L), total polyphenol content (4.08 vs 3.40 g/L), and viscosity (1.12 vs 1.08 cSt) values. The findings from this study are expected to be useful for baristas to control extraction efficiency/yield and manipulate brew compositional profiles to impart unique sensory characteristics of cold brew coffee beverages

Cinnamil- and Quinoxaline-Derivative Indicator Dyes for Detecting Volatile Amines in Fish Spoilage

Colorimetric indicators are versatile for applications such as intelligent packaging. By interacting with food, package headspace, and/or the ambient environment, color change in these indicators can be useful for reflecting the actual quality and/or monitoring distribution history (e.g., time and temperature) of food products. In this study, indicator dyes based on cinnamil and quinoxaline derivatives were synthesized using aroma compounds commonly present in food: diacetyl, benzaldehyde, p-tolualdehyde and p-anisaldehyde. The identities of cinnamil and quinoxaline derivatives were confirmed by Fourier transform infrared (FT–IR) spectroscopy, mass spectrometry (MS), 1H nuclear magnetic resonance (NMR) and 13C NMR analyses. Photophysical evaluation showed that the orange-colored cinnamil derivatives in dimethylsulfoxide (DMSO) turned to dark brownish coloration when exposed to strong alkalis. The cinnamil and acid-doped quinoxaline derivatives were sensitive to volatile amines commonly present during the spoilage in seafood. Quinoxaline derivatives doped by strong organic acid were effective as pH indicators for volatile amine detection, with lower detection limits than cinnamil. However, cinnamil exhibited more diverse color profiles than the quinoxaline indicators when exposed to ammonia, trimethylamine, triethylamine, dimethylamine, piperidine and hydrazine. Preliminary tests of acid-doped quinoxaline derivatives on fresh fish demonstrated their potential as freshness indicators in intelligent packaging applications

Fourier Transform Infrared and Physicochemical Analyses of Roasted Coffee

In this study, Brazilian coffee beans processed to different stages of roast at 210, 220, 230, and 240 °C were analyzed for pH value, titratable acidity, moisture content, and color lightness. Fourier transform infrared (FTIR) spectroscopy, in conjunction with principal component analysis, was conducted to study the effects of process time and temperature on the IR-active components of the acetyl acetate extract of the roasted coffee. The results showed that high-temperature–short-time resulted in higher moisture content, higher pH value, and higher titratable acidity when the beans were roasted beyond the start-of-second-crack stage, as compare to low-temperature–long-time process (LTLT). The LTLT process also resulted in greater IR absorbance for aldehydes, ketones, aliphatic acids, aromatic acids, and caffeine carbonyl bands on the FTIR spectra. Clusters for principal component score plots were well separated, indicating that the changes IR-active components in the coffee extracts, due to the different roasting treatments, can be discriminated by the FTIR technique. On the basis of the loading plots of principal components, changes of IR-active compounds in the coffee extract at various stages of roasting were discussed

Comparative study of hexanal as a dip and electrospun nanofiber mediated vapour treatments on enhancing the shelf life of pears

Hexanal slows down the ripening process in fresh produce by inhibiting the activity of phospholipase D, thereby increasing their shelf life. This study focused on comparing the single time exposure and continuous exposure of post-harvest of ‘Anjou’ and ‘Bartlett’ pears to hexanal by dipping or fumigating to enhance their shelf life. Continuous exposure of hexanal was achieved by developing a hexanal encapsulated fiber (HEF), which releases hexanal vapor due to the increased humidity (962% RH) in the container headspace as a result of respiration. The fruits were stored at cold storage (02C) conditions and compared with their capacity at normal room temperature (202C). Fruit parameters such as physiological loss of weight (PLW), firmness and total soluble solids (TSS) showed only minor differences between hexanal treated and untreated fruits. Between the two varieties ‘Anjou’ exhibited higher values than ‘Bartlett’, although it was minor. However, when the fruits are visually evaluated, the main aspect of consumer preference, HEF treatments had a better appeal in both varieties and in both conditions. ‘Bartlett’ responded better than ‘Anjou’ even in cold storage conditions, suggesting that there are varietal differences in their response to hexanal. Both hexanal treatments helped color retention and reduced fungal infection during under the storage conditions tested.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The Effect of Electrospun Polycaprolactone Nonwovens Containing Chitosan and Propolis Extracts on Fresh Pork Packaged in Linear Low-Density Polyethylene Films

Fresh meat products are highly perishable and require optimal packaging conditions to maintain and potentially extend shelf-life. Recently, researchers have developed functional, active packaging systems that are capable of interacting with food products, package headspace, and/or the environment to enhance product shelf-life. Among these systems, antimicrobial/antioxidant active packaging has gained considerable interest for delaying/preventing microbial growth and deteriorative oxidation reactions. This study evaluated the effectiveness of active linear low-density polyethylene (LLDPE) films coated with a polycaprolactone/chitosan nonwoven (Film 1) or LLDPE films coated with a polycaprolactone/chitosan nonwoven fortified with Colombian propolis extract (Film 2). The active LLDPE films were evaluated for the preservation of fresh pork loin (longissimus dorsi) chops during refrigerated storage at 4 °C for up to 20 d. The meat samples were analyzed for pH, instrumental color, purge loss, thiobarbituric acid reactive substances (TBARS), and microbial stability (aerobic mesophilic and psychrophilic bacteria). The incorporation of the propolis-containing nonwoven layer provided antioxidant and antimicrobial properties to LLDPE film, as evidenced by improved color stability, no differences in lipid oxidation, and a delay of 4 d for the onset of bacteria growth of pork chops during the refrigerated storage period

Antimicrobial coatings for controlling Listeria monocytogenes based on polylactide modified with titanium dioxide and illuminated with UV-A

The anti-listerial properties of biodegradable polylactide coatings modified with titanium dioxide have been studied. Free standing films were prepared by casting solutions prepared from titanium dioxide and previously extruded polylactide. It was demonstrated that polylactide alone could support 2.84 ± 0.10 log CFU reduction of Listeria monocytogenes when incubated at 23 °C for 2 h. However, the log reduction for Listeria could be increased to >4 log CFU with titanium dioxide:polylactide composites illuminated with UV-A. The inactivation kinetics of L. monocytogenes followed a diphasic die-off with an initial 30 min lag period then a progressive decline in bacterial levels over a further 90 min period. The anti-listeria effect of polylactide:titanium dioxide films was dependent on illumination with UV-A but independent on the concentration of TiO2 incorporated in the film within the range of 1–5% w/w. The mode of L. monocytogenes inactivation was via direct contact of the pathogen with the polylactide, in addition to the generation of oxygen radicals produced by excitation of the titanium dioxide. The composite film illuminated with UV-A was equally effective against Salmonella Typhimurium and Shiga toxin producing Escherichia coli. The coating was stable to 5 repeated sanitation cycles consisting of detergent and sodium hypochlorite rinses. The polylactide-titanium dioxide coating shows potential as an antimicrobial coating although further work is required to assess if the protective film can function under commercial conditions

High-Throughput Fabrication of Antibacterial Starch/PBAT/AgNPs@SiO₂ Films for Food Packaging

In this current work, antimicrobial films based on starch, poly(butylene adipate-co-terephthalate) (PBAT), and a commercially available AgNPs@SiO2 antibacterial composite particle product were produced by using a melt blending and blowing technique. The effects of AgNPs@SiO2 at various loadings (0, 1, 2, 3, and 4 wt%) on the physicochemical properties and antibacterial activities of starch/PBAT composite films were investigated. AgNPs@SiO2 particles were more compatible with starch than PBAT, resulting in preferential distribution of AgNPs@SiO2 in the starch phase. Infusion of starch/PBAT composite films with AgNPs@SiO2 marginally improved mechanical and water vapor barrier properties, while surface hydrophobicity increased as compared with films without AgNPs@SiO2. The composite films displayed superior antibacterial activities against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The sample loaded with 1 wt% AgNPs@SiO2 (SPA-1) showed nearly 90% inhibition efficiency on the tested microorganisms. Furthermore, a preliminary study on peach and nectarine at 53% RH and 24 °C revealed that SPA-1 film inhibited microbial spoilage and extended the product shelf life as compared with SPA-0 and commercial LDPE packaging materials. The high-throughput production method and strong antibacterial activities of the starch/PBAT/AgNPs@SiO2 composite films make them promising as antimicrobial packaging materials for commercial application