Plant-Based Phenolic Molecules as Natural Preservatives in Comminuted Meats: A Review

Comminuted meat products are highly susceptible to safety and quality degradation partly because of their large interfacial area in the emulsion. The food industry extensively uses synthetic chemical preservatives to delay that degradation which is caused by microbial growth, enzyme activities and oxidation reactions. However, due to the potential health damage (e.g., cardiovascular diseases, neurodegenerative diseases, cancers among others) synthetic preservatives in meat may cause, consumers are becoming skeptical to buy meat products containing such additives. In the meat industry, the interest of finding natural food preservatives is intensifying. Polyphenolic-rich plants used as natural food preservatives offer the best alternative for a partial or a complete replacement of their synthetic counterparts. They can be extracted from natural sources such as olives, fruits, grapes, vegetables, spices, herbs, and algae, and among others. The common feature of these phenolic compounds is that they have one or more aromatic rings with one or more -OH group which are essential for their antimicrobial and antioxidant properties. This review article is intended to provide an overview of the plant-based phenolic molecules used as natural food preservative, their antimicrobial and antioxidant mechanism of action, and their potential application in comminuted meat.

Overview of Studies on the Use of Natural Antioxidative Materials in Meat Products

Studies conducted in the past decade related to the use of natural antioxidants in meat products revealed the prevalent use of plant-based antioxidative materials added as powders, extracts, or dried or raw materials to meat products. The amount of antioxidative materials varied from 7.8 ppm to 19.8%. Extracts and powders were used in small amounts (ppm to grams) and large amounts (grams to >1%), respectively. Antioxidative materials used in meat products are mainly composed of phenolic compounds and flavonoids, which are able to inhibit lipid peroxidation of meat products, thereby preserving meat quality. However, the main ingredients used in processed meat products are the traditional additives, such as sodium erythorbate, sodium hydrosulfite, and synthetic antioxidants, rather than natural antioxidants. This difference could be attributed to changes in the sensory quality or characteristics of meat products using natural antioxidants. Therefore, novel research paradigms to develop meat products are needed, focusing on the multifunctional aspects of natural antioxidants.

Effects of Lotus (Nelumbo nucifera) Leaf Hot Water Extracts on the Quality and Stability of Eggs using Ultrasonication Treatment during Storage

This study was performed to investigate the effects of lotus leaf hot water extracts treatment on the quality and stability of eggs using impregnation treatment through ultrasonication during storage. A total of 480 eggs were categorized into four treatment groups (n=30 each)—non-treated (CON), soaked for 30 min in lotus leaf hot water extracts without ultrasonication (T1), sonicated in distilled water (T2), and sonicated in lotus leaf hot water extracts (T3)—and stored for 15 d at 30°C. The egg weight, Haugh unit (HU), egg grade, albumen height, yolk color, eggshell thickness, eggshell breaking strength, and weight loss were measured for egg quality assessment. 2-Thiobarbituric acid reactive substance (TBARS) and volatile basic nitrogen (VBN) contents were measured as stability indicators. Additionally, total phenolic contents (TPC), total flavonoid contents (TFC), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were evaluated. The HU, egg grade, albumen height, and yolk color of T3 were significantly higher than those of CON (p<0.05). No significant differences in eggshell thickness and eggshell breaking strength are observed among the groups. The weight loss of T3 was significantly lower than that of the other groups during storage (p<0.05). The application of lotus leaf hot water extracts also significantly reduced TBARS and VBN (p<0.05). The TPC, TFC, and DPPH radical scavenging activity of T3 were significantly higher than those of the other groups (p<0.05). These results suggest that lotus leaf hot water extracts may be useful as a natural ingredient for improving the quality and stability of eggs during storage.

Effects of natural nitrite source from Swiss chard on quality characteristics of cured pork loin

OBJECTIVE

This study was conducted to evaluate quality characteristics of cured pork loin with natural nitrite source from Swiss chard.

METHODS

Pork loin was cured in the brine and the ratio of water and fermented Swiss chard (FSC) solution in the brine was changed by 4:0 (Control), 3:1 (T1), 1:1 (T2), 1:3 (T3), 0:4 (T4) and pickled samples with 0.012% nitrite (PC) and nitrite free brine (NC) were considered as the control.

RESULTS

The pH values of cured pork loins with FSC were decreased with increasing addition level of FSC. Cooking loss was not significantly different among all treatments. T4 had the lowest value in moisture content and lightness value and the highest value in curing efficiency. The redness value of T4 was not significantly different from that of PC in raw. After cooking, however, it was higher than that of PC. The yellowness value of cured pork loin added with FSC was increased with increasing level of FSC. Volatile basic nitrogen content of cured pork loin added with FSC was higher than PC and NC. Thiobarbituric acid reactive substance value of cured pork loin added with FSC was decreased with increasing FSC level. Residual nitrite level and shear force were increased with increasing FSC level. In the sensory evaluation, sensory score for flavor, off-flavor, hardness, chewiness, juiciness, and overall acceptability were not significantly different among all treatments. However, sensory score for color was increased when the concentration of FSC added to pork loin was increased.

CONCLUSION

Fermented Swiss chard solution had a positive effect on redness, lipid oxidation. Although there were shown in protein decomposition and sensory, Swiss chard can be replaced sodium nitrite as natural curing agent.

Quality of Sliced Cured Pork Loin with Spinach: Effect of Incubation Period with Starter Culture

An increasing concern about the usage of chemical additives in meat products has resulted in the use of natural ingredients instead of chemical additives in meat products. Therefore, this study aimed to investigate the effect of incubation period on the physicochemical characteristics of meat products cured with spinach and starter culture containing Staphylococcus carnosus. The pH, color, TBARS lipid oxidation, volatile basic nitrogen, residual nitrite content, and microbial number in cured pork loin were determined by incubating it with spinach and starter culture for the following durations: 3, 6, 9, 12, 24, and 48 h. The pH and TBARS values of cured pork loin incubated with spinach and starter culture decreased in a time-dependent manner. An increase in the incubation time from 3 to 48 h resulted in a significant increase in the redness and volatile basic nitrogen content. The residual nitrite content was observed to be maximum in samples from the I48 group followed by the control (+), preconverted nitrite group, and I24 groups. Thus, we found that incubation with spinach and starter culture for 24 h yields a good-quality cooked sliced cured pork loin.

Effect of aged garlic powder on physicochemical characteristics, texture profiles, and oxidative stability of ready-to-eat pork patties

Objective

The aim of this study was to investigate the effects of aged garlic powder (AGP) on physicochemical characteristics, texture profiles, and oxidative stability of ready-to-eat (RTE) pork patties.

Methods

There were five treatment groups: a control; 1% fresh garlic powder (T1); 0.5%, 1%, and 2% AGP (T2, T3, and T4). Pork patties with vacuum packaging were roasted at 71°C for core temperature, stored at 4°C for 14 d, and then reheated for 1 min using a microwave.

Results

The AGP groups showed a lower the level of lipid oxidation and higher thiol contents than the control and T1. The pH value of the control increased whereas that of aged garlic groups decreased after re-heating process. In addition, the redness significantly increased with increasing level of AGP whereas the redness of the control and T1 decreased after re-heating process. T4 added patties improved textural and sensory properties compared to the control.

Conclusion

The results of this study suggest that AGP addition to RTE pork patties can improve their sensory characteristics and oxidative stability.

Lotus Flavonoids and Phenolic Acids: Health Promotion and Safe Consumption Dosages

Nelumbo nucifera Gaertn., also known as the sacred lotus, is extensively cultivated in Southeast Asia, primarily for food and as an herbal medicine. This article reviews studies published between 1995 and 2017, on flavonoid and phenolic acid profiles and contents of 154 different cultivars of lotus. So far, some 12 phenolic acids and 89 to 90 flavonoids (47 flavonols, 25 to 26 flavons, 8 flavan-3-ols, 4 flavanons, and 5 anthocyanins) have been isolated from different parts of the lotus plant, including its leaves (whole leaf, leaf pulp, leaf vein, and leaf stalk), seeds (seedpod, epicarp, coat, kernel, and embryo), and flowers (stamen, petal, pistil, and stalk), although not all of them have been quantified. Factors affecting flavonoids and phenolic acid profiles, including types of tissues and extracting factors, are discussed in this review, in order to maximize the application of the lotus and its polyphenols in the food industry. Health promotion activities, attributed to the presence of flavonoids and phenolic acids, are described along with toxicology studies, illustrating appropriate usage and safe consumption dosages of lotus extracts. This review also presents the controversies and discusses the research gaps that limit our ability to obtain a thorough understanding of the bioactivities of lotus extracts.

Effect of fermented red beet extracts on the shelf stability of low-salt frankfurters

The effect of fermented red beet (FRB) on shelf-life of low-salt frankfurters stored for 4 weeks was investigated. The pH, volatile basic nitrogen (VBN), lightness, and yellowness of frankfurters decreased with increasing levels of FRB, whereas the redness of frankfurters increased with increasing levels of FRB. The VBN, thiobarbituric acid reactive substance values, total viable count, and redness of all treatments decreased with increasing period of refrigeration storage. The appearance, color, and juiciness scores of the control and treatments decreased with increasing period of refrigeration storage. However, there was no significant (p > 0.05) difference among the treatments except for the color of T3 (3.0% FRB) and juiciness of T4 (5.0% FRB). The flavor, tenderness, and overall acceptability scores of all the treatments decreased with increasing storage periods. These results demonstrated that FRB can be added to low-salt frankfurters to maintain their qualities and extend the shelf-life of refrigerated storage.

Quality and Sensory Characteristics of Reduced-fat Chicken Patties with Pork Back Fat Replaced by Dietary Fiber from Wheat Sprout

The effects of reducing pork fat levels from 20% to 15% or 10% by partially substituting pork back fat with wheat sprout fiber in reduced-fat chicken patties were investigated. Approximate composition, energy value, pH, color, cooking loss, reduction in diameter, reduction in thickness, shear force, and sensory properties were determined. Moisture content, ash contents, yellowness of uncooked and cooked reduced-fat chicken patties with wheat sprout were higher than those in the control, while displaying fat content, calorie content, and pH of uncooked and cooked lower in reduced-fat chicken patties than in the control. Cooking loss, reduction in diameter, and reduction in thickness were the highest in the reduced-fat chicken patties with 10% fat level. Cooking loss, reduction in diameter, and reduction in thickness were decreased when fat levels and wheat sprout levels were increased. Control samples without wheat sprout dietary fiber had significantly (p<0.05) higher color and flavor scores compared to reduced-fat chicken patties containing wheat sprout dietary fiber. The overall acceptability of the control and treatment with 15% fat and 2% wheat sprout dietary fiber (T3) was the highest. Therefore, 15% fat level in reduced-fat chicken patties with the addition of 2% wheat sprout dietary fiber can be used to improve the quality and sensory characteristics of regular-fat chicken patties containing 20% fat level.

Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak

The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (p<0.05), whereas protein content, redness value (a*-value), hardness, gumminess, and chewiness of superheated steam cooked chicken steak was lower than that in the other cooking treatments (p<0.05). Fat content and ash content, springiness, and cohesiveness were not significantly different among the chicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p<0.05), whereas no difference in flavor scores were observed among the other treatments (p>0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak.

Combined Effects of Mugwort Herb and Vitamin C on Shelf-Life of Vacuum-Packed Seasoned Pork

This study was performed to investigate the possibility of the addition of mugwort herb extract (MH) and vitamin C (VC) alone (0.05%) and in combination (0.05% each) on shelf-life of seasoned pork. The combination of VC+MH demonstrated a significant reduction in thiobarbituric acid reactive substances, and volatile basic nitrogen in seasoned pork. Also, the pH values, total lactic acid concentration, lactic acid bacteria count, and the sensory properties (discoloration, flavor, and overall acceptability) of seasoned pork were not significantly affected by adding MH and/or VC. All seasoned pork were rejected by sensory panel when LAB count reached levels of 5-6 Log CFU/g, TLA concentration has been above a level of 3.6-3.9 mg lactic acid/g, and pH values ranged from 5.31-5.51 (15 d). Therefore, the findings showed that spoilage of seasoned pork does not appear to be the result of lipid oxidation, but is caused by lactic acid producing bacteria which result in sour odor.

Changes in Quality Characteristics of Pork Patties Containing Multilayered Fish Oil Emulsion during Refrigerated Storage

This study was performed to determine the effect of multilayered fish oil (FO) emulsion without or with trans-cinnamaldehyde on pork patties. Multilayered FO (-primary, -secondary, -tertiary) emulsions were prepared using a layer-by-layer deposition technique with Tween 20, chitosan, and low methoxyl pectin, and were added to pork patties at the same concentration. Pork patties were then stored for 20 d in a refrigerator (5℃) to study changes in quality. The results showed that the pH value of all samples significantly decreased but cooking loss increased during storage (p<0.05). However, water-holding capacity and moisture content showed no remarkable difference between treatments and storage periods (p>0.05). All pork patties containing multilayered FO (treated samples) showed higher values for lightness and significantly lower values for yellowness compared to control pork patties (untreated sample). Lipid oxidation was higher in treated pork patties than in control pork patties during storage. In addition, lipid oxidation and total viable bacterial count in pork patties decreased as the number of coating layers increased. However, hardness, cohesiveness, and springiness of all samples showed no significant change during storage (p>0.05) as compared to fresh pork patties. Furthermore, these did not remarkable change with addition of trans-cinnamaldehyde in all pork patties. From our results, we suggest that FO emulsion did not affect the texture characteristics of fresh pork patties, indicating that it could be used to improve the quality of pork patties by contributing high-quality fat such as unsaturated fatty acids.

Effects of Lemon Balm on the Oxidative Stability and the Quality Properties of Hamburger Patties during Refrigerated Storage

This study was performed to investigate the effects of lemon balm (Melissa officinalis L.) on various quality and antioxidant activity of hamburger patties. Lemon balm extract (LBE) showed the highest amount of total polyphenol (801.00 mg TAE/g DW) and flavonoids (65.05 mg RA/g DW). The IC50 value of DPPH hydroxyl scavenging of LBE was 132 μg/mL. The hamburger patties were prepared by 0% (N), 0.1% (L1), 0.5% (L2), and 1.0% (L3) of the lemon balm powder. The addition of lemon balm powder increased the chewiness value, but did not affect the hardness, cohesiveness, and springiness values. Lemon balm powder had positive effects on sensory evaluation of patties. The pH of all patties decreased with longer storage period. 2-Thiobarbituric acid value, volatile basic nitrogen content, and the total microbial counts of hamburger patties in the L3 group were lower, compared to those of the normal (N group). In conclusion, the L3 group had significantly delayed lipid peroxidation compared to other treatment groups. However, the addition of lemon balm powder into patties showed no significantly influence on proximate composition, calorie contents, water holding capacity and cooking loss of patties. Therefore, lemon balm might be a useful natural antioxidant additive in meat products.