Boning and Storage Temperature Effects on the Attributes of Soft Jerky and Frozen Cooked Free-flow Mince

Hot or cold boning and frozen or chilled storage of beef for 1 mo had no effect on sensory panel acceptability of soft beef jerky (easier to chew than traditional jerky) processed using a two step drying method and a frozen cooked free-flow mince (ground beef) made from the beef. For jerky, panel scores for texture and overall acceptability decreased with increased peak force and softness scores increased with increased final yield. Sensory panelists disliked the greyish-brown color of the cooked free-flow mince. The most acceptable free-flow mince was produced by cooking Alogs@ to 73°C, then mincing at –6°C. The degree of freeflowness and the amount of fines tended to increase with decreasing mincing temperature.     

Functional and bioactive properties of fish protein hydolysates and peptides: A comprehensive review

Global fish processing industries dispose of fish wastes that account for more than 60% of processed fish biomass. In lieu of environmental pollution and disposal problems, these wastes are used to produce fish silage, fishmeal and sauce. They are also utilized for the production of value added products such as proteins, hydrolysates, bioactive peptides, collagen and gelatin. Research on the production of fish protein hydroysates (FPHs) presently focuses on maximizing the industrial potential of fish wastes. Since bioactive peptides containing amino acids hold properties of great interest, this paper reviews current research on the functional and bioactive properties of FPHs with an additional focus on gaps between fish and other hydrolysates, as well as current and future trends for the productive utilization of FPHs.     

Functional Stability of Antioxidant-washed, Cryoprotectant-treated Beef Heart Surimi During Frozen Storage

Beef heart surimi was prepared in the presence or absence of propyl gal late and blended with or without cryoprotectants (sorbitol, sucrose) prior to frozen storage at 15°, 29°, and 70°C up to 52 wk. Protein solubility, gelling characteristics, water-holding capacity, cooking yield, and emulsifying properties decreased during storage at 15° and 29°C for control surimi (without cryoprotectants). Propyl gallate alone did not influence functionality changes. However, functional properties were largely protected by cryoprotectants as well as at 70°C independent of cryoprotectants. Thus, unless extremely low temperatures are used, beef heart surimi subjected to long-term cryogenic storage should be mixed with cryoprotectants and antioxidants to preserve functionality.     

Glycine Betaine-Mediated Protection of Peas (Pisum sativum L.) During Blanching and Frozen Storage

We used glycine betaine (5–20% w/v) for blanching green peas (100°C, 60 s), and their subsequent freezing and storage (–20°C, 90 days). Blanching after the addition of glycine betaine at ≥10% (w/v) followed by a 90 day storage period which resulted in the most desirable outcome: higher vitamin C levels, a superior green color, enhanced organoleptic quality and texture, and improved retention of peroxidase and lipoxygenase activity relative to control peas (no glycine betaine added). Microscopic characterizations of control and treated peas revealed that glycine betaine acts as a cryoprotectant which maintains cellular integrity. Glycine betaine (10% w/v) could be used commercially for production of frozen peas with better quality attributes.     

Structural and Functional Properties of Ovalbumin Glycated by Dry-Heating in the Presence of Maltodextrin

Ovalbumin is the main constituent of egg white protein. Improvements in the functional properties of ovalbumin are of great importance in the food industry. Therefore, in this article, the structural and functional properties of ovalbumin, which were glycated by dry-heating, were investigated. The micrographs showed that glycated ovalbumin was smaller and more homogeneous than native and dry-heated ovalbumin. Although changes in the random coil structure of ovalbumin measured by circular dichroism were mild, increased surface hydrophobicity and decreased tryptophan fluorescence intensity were observed following glycation. Glycation improved the stability against heat induced insolubility, emulsifying properties, water and oil binding capacity of ovalbumin. These results suggested that dry-heating glycation is a useful method for improving the functional properties of ovalbumin. The attention on the structural and functional changes in this work will be contributed to the understanding of the structure-function relationship. These insights would have important implications for the creation of desirable structure and functional properties of food products.     

ATPase and Lactate Dehydrogenase Activities in Frozen Stored Fish Muscle as Indices of Cold Storage Deterioration

The effect of prolonged cold storage on muscle adenosine triphosphatase (ATPase) and lactate dehydrogenase (LDH) activities was studied in a variety of fresh water and brackish water fish. Decrease in enzyme activity was observed in all samples stored frozen (- 20°C) over a period of 180 days. Highly significant negative correlation was observed between enzyme activity and frozen storage period with mullet, pearlspot, milk fish and tilapia. Significant linear correlations were observed between decrease in enzyme activities and other biochemical indices and sensory scores. The results indicated that loss of activities of ATPase and LDH in fish muscle was significantly related to early changes in quality of frozen stored fish.     

Changes in Electrophoretic Patterns of Gadoid and Non-gadoid Fish Muscle during Frozen Storage

Sodium dodecyl sulfate polyacrylamidc gel electrophoresis of fish muscle during frozen storage showed that a crosslinked protein of 280,000 daltons formed with gadoids, whereas this band did not occur with non-gadoid fish species. For cod, 20 days at -7°C are needed for the crosslink to appear, whereas for whiting only 3 days arc needed. Formaldehyde (FA) may be responsible for the crosslinking. Adding ascorbic acid to cod mince prior to freezing accelerated dimcthylamine and FA formation during frozen storage and accelerated the formation of the crosslinked protein, while leaving cod fillets on ice for 10 days prior to freezing, reduced the Instron hardness and the crosslinked protein did not appear with 50 days of frozen storage at -7°C.     

Textural Changes and Functional Properties of Cod Mince Proteins as Affected by Kidney Tissue and Cryoprotectants

The addition of cryoprotectants, e.g., a mixture of sucrose and sorbitol or polydextrose (PDT) with sodium hexametaphosphate (SHMP), to improve the texture and water retention properties of cod mince with kidney tissue (modified mince) was studied at ?47°C. Kidney tissue provided trimethylamine oxide (TMAO) demethylase to accelerate dimethylamine (DMA) and formaldehyde formation. Expressible moisture (EM), water uptake ability (WUA), protein solubility, cook loss, DMA production, and textural profile analysis were determined to detect changes in modified mince during frozen storage. Modified mince with SHMP and sucrose/sorbitol or PDT at ?14°C had improved EM, WUA, and cook loss and was more tender.     

Changes in Quality Attributes During Storage of High-Pressure and Thermally Processed Pineapple Puree

The primary issue of the pineapple puree processing industry is its limited stability. The study compares the quality changes in high-pressure and thermally processed pineapple puree at different storage conditions and estimates the shelf-life. The untreated (S1) and treated samples (S2, S3, and S4 treated at 600 MPa/50 °C/13 min, 600 MPa/70 °C/20 min, and 0.1 MPa/95 °C/12 min, respectively) packed in ethylene vinyl alcohol (EVOH) and multi-layered (ML) polyethylene terephthalate (PET) pouches were stored up to 125 days at 5, 15, and 25 °C. The total color change (?E*) and browning index during storage increased according to zero-order kinetic model, whereas ascorbic acid (AA), total phenolics, and total antioxidant capacity followed the first-order decay. The overall sensory acceptability (OA) of S2 was higher than both S3 and S4 at 5 °C, and it dropped rapidly at 15 and 25 °C. The activity of polyphenol oxidase and pectin methylesterase in S3 and S4 was less than 10 % up to 120 days at 5 °C. The consistency (κ) and residual enzyme activity in S2 decreased with storage duration and temperatures. For estimating the shelf-life, the change in OA was crucial for S2 and S3, whereas retention of AA served as the critical parameter for S4. The sample S2 packed in ML pouch was found to be the best sample having the shelf-life (microbial count?<?6-Log cfu g^?1, ?E*?<?12, OA?>?5, and AA?>?200 mg kg^?1) of 120, 50, and 25 days at 5, 15, and 25 °C, respectively.     

Sensory Evaluations and Changes in Peroxidase Activity During Storage of Frozen Green Beans

Total, soluble and bound peroxidase activities were studied on frozen green beans stored under proper conditions (–18°C, -22°C, and in display freezer) and under adverse conditions (with temperature fluctuations). Blanching inactivated the enzyme; there was no regeneration for 12 mo at -22°C, but a slight regeneration at - 18°C. Sensory quality of the properly stored product was acceptable 1 yr or longer. Storage in a display freezer over 60 days did not affect peroxidase activity. Temperature fluctuations were deleterious for sensory quality and total peroxidase activity was only slightly regenerated.     

Effect of Detoxification on Conformational and Functional Properties of Jatropha curcas Proteins

The effects of detoxification process on conformational and functional properties of Jatropha curcas proteins were investigated. The molecular fractions and structure of proteins were affected more easily by the detoxification process. Compared with the proteins in Jatropha curcas meal, the detoxification process decreased the thermal stability and led to an increase in the surface hydrophobicity with a decrease in the contents of sulfhydryl and disulfide bond of proteins in detoxified Jatropha curcas meal. These conformational sand compositional changes in proteins influenced by the detoxification process, contributed to the relatively good changes in functional properties of detoxified Jatropha curcas meal, such as solubility, water and fat holding capacities, emulsifying properties, and foaming properties. Therefore, the detoxification treatment was not only a promising way to detoxify, but also an effective means to improve the functional properties of detoxified Jatropha curcas meal.     

贮藏期UHT奶中蛋白质组成结构及其糖基化的变化

通过测定UHT奶在贮藏过程中蛋白水解,蛋白在胶束相和乳清相的分布,乳蛋白糖基化位点变化,探究乳蛋白在贮藏过程中性质的变化.结果表明贮藏过程中UHT奶中菌落总数增大,纤溶酶含量增大.UHT奶在内外源酶的作用下乳蛋白发生不同程度的水解.热处理导致从胶束表面脱落的κ-CN和乳清蛋白以热诱导聚合物的形式,在贮藏过程中重新结合到...     

花生粉,花生浓缩蛋白制备工艺及功能特性的研究

对花生蛋白，特别是花生浓缩蛋白的制备工艺进行了研究。对浓缩蛋白的三种制备方法进行了分析比较，并将产品的功能特性与大豆浓缩蛋白进行了对照。     

Functional and bioactive properties of collagen and gelatin from alternative sources: A review

The rising interest in the valorisation of industrial by-products is one of the main reasons why exploring different species and optimizing the extracting conditions of collagen and gelatin has attracted the attention of researchers in the last decade. The most abundant sources of gelatin are pig skin, bovine hide and, pork and cattle bones, however, the industrial use of collagen or gelatin obtained from non-mammalian species is growing in importance. The classical food, photographic, cosmetic and pharmaceutical application of gelatin is based mainly on its gel-forming properties. Recently, and especially in the food industry, an increasing number of new applications have been found for gelatin in products such as emulsifiers, foaming agents, colloid stabilizers, biodegradable film-forming materials and micro-encapsulating agents, in line with the growing trend to replace synthetic agents with more natural ones. In the last decade, a large number of studies have dealt with the enzymatic hydrolysis of collagen or gelatin for the production of bioactive peptides. Besides exploring diverse types of bioactivities, of an antimicrobial, antioxidant or antihypertensive nature, studies have also focused on the effect of oral intake in both animal and human models, revealing the excellent absorption and metabolism of Hyp-containing peptides. The present work is a compilation of recent information on collagen and gelatin extraction from new sources, as well as new processing conditions and potential novel or improved applications, many of which are largely based on induced cross-linking, blending with other biopolymers or enzymatic hydrolysis.     

Non-Volatile Organic Acids,pH and Titratable Acidity Changes in Pineapple Fruit Slices During Frozen Storage

Effects of freezing and frozen storage on pH, titratable acidity and non-volatile organic acids of two pineapple fruit cultivars, Smooth Cayenne and Red Spanish, were studied. Pineapple fruit was frozen as slices in a cold room at −18°C and stored at this temperature for a 12 month period. A negative correlation was found between pH and titratable acidity in the two cultivars throughout frozen storage ( r =-0·67 for Smooth Cayenne and r =-0·71 for Red Spanish). Non-volatile organic acids were determined by high performance liquid chromatography. The major components were citric and L-malic acids. A high correlation was found between these two acids during frozen storage ( r =0·75 in Smooth Cayenne and r =0·78 in Red Spanish). There were significant differences ( P⩽ 0·01) in pH and titratable acidity between the two studied varieties after a year of frozen storage. Significant differences ( P⩽ 0·05) were found in pH values during frozen storage in cv Smooth Cayenne and in citric and L-malic acids in cv Red Spanish. Freezing preservation of pineapple fruit slices led to minimal chemical changes after a year of frozen storage.     

Functional properties of fish protein hydrolysates from Pacific whiting(Merluccius productus) muscle produced by a commercial protease

Pacific whiting (Merluccius productus) muscle was used to produce hydrolysates with 10%, 15% and 20% degree of hydrolysis (DH) using the commercial protease Alcalase^® and were characterized at pH 4.0, 7.0 and 10 according their solubility, emulsifying and foaming properties. Protein recovered in soluble fractions increased proportionally with the hydrolytic process, yielded 48.6 ± 1.9, 58.6 ± 4.1 and 67.8 ± 1.4 of total protein after 10%, 15% and 20% DH, respectively. Freeze-dried hydrolysates presented almost 100% solubility (p > 0.05) at the different pHs evaluated. Emulsifying properties (EC, EAI and ESI) were not affected by DH as most samples showed similar (p > 0.05) results. Higher EC (p ? 0.05) than sodium caseinate, used as control, were obtained at pH 4 for most hydrolysates. Hydrolysates showed very low foaming capacity not affected by pH; but foam stability was equal or even better (p > 0.05) than bovine serum albumin (BSA), except at pH 4.0. Results suggest that hydrolysates from Pacific whiting muscle can be produced with similar or better functional properties than the food ingredients used as standards.     

Changes in Some Biochemical Indices of Stability of Broiler Chicken Actomyosin at Different Levels of Sodium Bicarbonate in Presence and Absence of Sodium Chloride

This study examined some physicochemical properties of actomyosin isolated from pre-rigor chicken breast muscle (Pectoralis major) to gain insight on its interaction with 0.2–1.0M sodium bicarbonate (NaHCO₃) either with or without 3% sodium chloride (NaCl). NaHCO₃ has been a frequent quality raiser with respect to water holding capacity of meat, which is adversely affected at low pH. This study document a remarkable inactivation of ATPases and the weakening of actin-myosin interaction with increasing molarity of NaHCO₃, irrespective of the presence or absence of NaCl. Similarly, there was a concomitant increase in turbidity of soluble fraction, increase in total protein solubility and reactive SH groups. The observations on protein solubility/insolubility are supported by SDS-PAGE profiles. Therefore, the conformational changes induced by NaHCO₃ are concentration dependent and appear different from those during thermal transitions. The findings suggest that low concentration of NaHCO₃ may be more suitable component of marinades, since it affects the main myofibrillar contractile complex less adversely.