Antioxidant activity of spice extracts in a liposome system and in cooked pork patties and the possible mode of action

Three experiments were conducted to assess the antioxidant efficacy of spice extracts in cooked meat. In experiment 1, antioxidant activity of 13 common spice extracts was screened in a liposome system. Six of the extracts (clove, rosemary, cassia bark, liquorice, nutmeg, and round cardamom), identified to have the greatest total phenolic contents, were strongly inhibitory of TBARS formation. In experiment 2, 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric-reducing power, and metal chelation of these six spice extracts were evaluated. Clove exhibited the greatest reducing power, and all had strong DPPH scavenging activity. In experiment 3, clove, rosemary, and cassia bark extracts were further tested for in situ antioxidant efficacy. Cooked pork patties containing these spice extracts had markedly reduced TBARS formation and off-flavour scores but a more stable red colour, during storage. The results demonstrated strong potential of spice extracts as natural antioxidants in cooked pork products.     

洋葱皮乙醇提取物对生鲜猪肉色泽、脂质和蛋白质氧化稳定性的影响

为研究洋葱皮乙醇提取物(ethanol extract of onion skins,EEOS)对生鲜猪肉色泽褐变,脂肪和蛋白质氧化以及微生物侵染程度的影响,并与空白对照组和抗坏血酸(ascorbic acid,VC)处理组进行比较,以猪肉亮度值L?、红度值a?,以及高铁肌红蛋白(metmyoglobin,MetMb)...     

Effect of a brown seaweed (Laminaria digitata) extract containing laminarin and fucoidan on the quality and shelf-life of fresh and cooked minced pork patties

A spray-dried seaweed extract containing laminarin (L, 9.3%) and fucoidan (F, 7.8%) (L/F extract) from brown seaweed (Laminaria digitata) was added directly to minced pork (M. longissimus dorsi) (LD) at levels of 0.01%, 0.1% and 0.5% (w/w). Fresh and cooked minced pork patties were stored in modified atmosphere packs containing 80% O₂:20% CO₂ and 70% N₂:30% CO₂, respectively, for up to 14 days at 4 °C. The L/F extract reduced the surface redness (‘a*’ values) of fresh patties as a function of concentration. The L/F extract (0.5%) exerted the greatest lipid pro-oxidant activity in fresh patties. The L/F extract (0.5%) significantly decreased (P < 0.05) lipid oxidation in cooked patties. The L/F extract had no effect on the microbiological status, pH, water holding capacity (WHC) or cook loss of patties. Pork patties containing 0.01% L/F were preferred by sensory panellists. Further research will focus on the use of refined purified seaweed extracts in functional meat products.     

洋葱、生姜、大蒜提取物对冷却肉保鲜效果的研究

研究了洋葱、生姜和大蒜提取物对冷却肉的冷藏保鲜效果。冷却肉分别用洋葱、生姜和大蒜提取物溶液浸泡3min,以蒸馏水浸泡作为对照,晾干后用聚乙烯薄膜密封包装,于4℃下贮藏,分别测定冷却肉在冷藏期间感官指标、保水能力与汁液流失率、pH与酸度、挥发性盐基氮（TVB-N）和硫代巴比妥酸反应物值（TBARS）的变化规律。结果表明:洋葱、生姜和大蒜提取物均能显著抑制冷却肉冷藏过程中感官评分和酸度的下降,延缓汁液流失率及pH的上升,提高冷却肉的保水能力,有效阻止TBARS值及TVB-N值的增加,使冷却肉贮藏品质得到明显改善;三者中以大蒜提取物保鲜效果最佳,可将冷却肉的保质期延长到12d以上。      

The storage stability and textural, physico-chemical and sensory quality of low-fat ground pork patties with Carrageenan as fat replacer

Low‐fat ground pork patties (<10% total fat) made with carrageenan added at either 0.25, 0.50 or 0.75% final concentration were processed and the compositional and sensory characteristics compared with control patties which contained 20% fat. The moisture content of raw and cooked low‐fat patties was significantly (P < 0.05) higher than control patties because of greater amounts of water added during formulation. Cooking yield, fat and moisture retention also improved significantly (P < 0.05) in low‐fat patties that had carrageenan incorporated when compared to a control product. The dimensions of the low‐fat patties were maintained better than those of the control product during cooking. The sensory attributes of low‐fat patties with 0.5% carrageenan were similar to those of the high‐fat control. The lipid profile revealed as much as a 47.7 or 44.1% decrease in total lipids and cholesterol content respectively, compared with the controls. The calorie content was reduced by 31.1% in low‐fat cooked patties compared with the controls. The texture profile of low‐fat patties that had been made with 0.5% carrageenan were similar to control patties with only a slight increase in hardness and gumminess in the low‐fat product. The low‐fat ground pork patties made in the present study remained stable without any appreciable loss of physico‐chemical, microbiological and organoleptic quality during refrigerated storage (4 ± 1 °C) for 21 and 35 days in aerobic and vacuum packaging respectively.     

Changes in physicochemical properties of pork myofibrillar protein combined with corn starch and application to low-fat pork patties

The aim of this study was to evaluate the physicochemical properties of pork myofibrillar protein (MP) gels as affected by different additional levels of corn starch and microbial transglutaminase (MTGase) and applied to pork patties at two levels of corn starch. MPs with MTGase have higher properties than those without MTGase, except cooking loss (CL), which improved with higher corn starch concentrations. Although gel strength did not differ among the treatments, microstructures of corn starch were swollen, which proved that they were holding water. When corn starch was added, CL and thawing loss decreased, but shear value increased. The diameter shrinkage values of pork patties decreased with increasing corn starch concentrations. In addition, the pork patties with 2 g/100 g corn starch have a higher water-holding capacity than the controls. The meat industry could use 1.0 g/100 g corn starch as a water-binding agent to manufacture pork patties.     

Effects of glutinous rice flour on the physiochemical and sensory qualities of ground pork patties

The study investigated the effects of glutinous rice flour (GRF) on the quality of ground pork patties. Ground pork patties with 3% of GRF showed better quality compared to addition of 1% and 5% of GRF. Addition of 3% GRF was further compared with 0.5% carrageenan, 3% soy protein isolate, 3% corn starch and 3% potato starch in ground pork patties. The cooking yield in GRF group was significantly higher than that of other treatments due to the increase in moisture and fat retentions (P < 0.05). Comparing with other groups, GRF showed lower texture profile values for hardness and chewiness (P < 0.05). The ground pork patties with GRF were juicier, more tender and showed better flavor and overall acceptability compared to control and the treatments with other additives (P < 0.05). The results indicate that GRF could be an effective functional ingredient in ground pork patties.     

花椒提取物对调理猪肉饼冷藏期间品质的影响研究

探究不同添加量的花椒提取物对调理猪肉饼冷藏期间品质及氧化程度的影响。将0.01%、0.02%和0.03%的花椒提取物添加到调理猪肉饼中,研究其在1、4、7、10 d冷藏期间的pH、颜色、质构、硫代巴比妥酸值(thiobarbituric acid reactive substance,TBARS)和巯基值的变化,并与0.02%二丁基羟基甲苯(butylated hydroxytoluene,BHT)作比较。研究结果表明,添加花椒提取物对调理猪肉饼冷藏期间的pH、颜色无显著影响(p>0.05),在一定程度上降低了其硬度和咀嚼性。此外,添加花椒提取物可显著降低猪肉饼脂肪氧化和蛋白质氧化程度(p<0.05)。当添加量为0.01%和0.02%时,花椒提取物处理组抑制脂肪氧化的效果与0.02%的BHT效果相当,而当添加量增加至0.03%时,花椒提取物组抗脂肪氧化效果优于0.02%的BHT,且其蛋白氧化程度在整个冷藏期间均显著低于对照组(p<0.05),表明花椒提取物可有效抑制猪肉饼中脂肪和蛋白质氧化,其中0.03%花椒提取物组效果最好,甚至优于0.02%的BHT。     

Antioxidant activity of black currant (Ribes nigrum L.) extract and its inhibitory effect on lipid and protein oxidation of pork patties during chilled storage

This experiment was conducted to assess the antioxidant efficacy of black currant (Ribes nigrum L.) extract (BCE) in raw pork patties during chilled storage. The extracting conditions of frozen BCE including ethanol concentrations (0-100%) and extracting times (0.25-12h) were studied. BCE extracted with 40% ethanol for 2h had the highest anthocyanin content, the strongest radical scavenging activities as well as the second strongest reducing power. BCE was condensed and added to pork patties at 5, 10 or 20 g/kg. Compared with the control, BCE treatments significantly decreased the thiobarbituric acid-reactive substance values and carbonyls formation and reduced the sulfhydryl loss of pork patties in a dose-dependent manner (P<0.05), which showed that the BCE significantly inhibited lipid and protein oxidation. The BCE-treated patties showed significantly higher redness (P<0.05) than the control. The findings demonstrated strong potential for BCE as a natural antioxidant in meat and meat products.     

Evaluation of lipid oxidation in horse mackerel patties covered with borage-containing film during frozen storage

Lipid oxidation of horse mackerel (Trachurus trachurus) patties covered with fish gelatin-based films containing a borage seed extract were evaluated, including commonly used analytical indexes (peroxide value, thiobarbituric acid reactive substances, polyene ratio), as well as determination of volatile compounds, quantitation of oxidized triacylglycerols and analysis by Fourier transform infrared (FTIR) spectroscopy, during 240 days of frozen storage and subsequent thawing and 4 days-chilling. Vacuum packaged-patties and control uncovered patties were also tested for comparative purposes. Methods applied to evaluate lipid oxidation in extracted lipids, i.e. peroxide value, quantitation of oxidized triacylglycerols and FTIR, clearly provided a better picture of the oxidation progress and led to similar conclusions. Film had protective effects on lipid oxidation of horse mackerel patties throughout frozen storage and particularly after thawing and chilled storage. Furthermore, when compared to vacuum packaging, film was found to be similarly effective until advanced stages of oxidation were reached and exerted enhanced protection once samples were thawed and exposed to air oxygen under chilling temperature; with the additional advantage of increasing the antioxidant capacity of muscle.     

Effect of sprouting on physicochemical,antioxidant and flavonoid profile of onion varieties

This study investigated the impact of sprouting in four Indian onion varieties (Punjab White, Punjab Naroya, PRO‐6 and Commercial). Results showed significant (P < 0.05) increase in protein, crude fibre, ascorbic acid content, total phenol content, total flavonoid content, antioxidant activity, anthocyanin content and significant (P < 0.05) decrease in total carbohydrate, energy value and hardness due to sprouting in all the four varieties. HPLC analysis revealed irregular pattern of increase and decrease in flavonoid components. There was no particular trend observed within analysed flavonols due to sprouting in all the four varieties except with the maximum increase in quercetin (219.3–287.4 mg kg^?1), kaempferol (13.8–17 mg kg^?1), myricetin (34.6–40.9 mg kg^?1), quercetin‐3?‐glucoside (2.9–4.1 mg kg^?1) and quercetin‐4?‐glucoside (83–87.1 mg kg^?1) in case of PRO‐6 variety only. The present research work implied sprouting to be beneficial in onion as nutritional and functional potential of all the four onion varieties was improved by sprouting.     

贮藏条件对猪肉糜氧化效应的影响

将肥瘦比为1:1的猪糜于-18、-24、-40℃三种条件下贮藏,每10d取样一次,通过测定酸价（AV）、过氧化值（POV）和硫代巴比妥酸（TBARS）值,研究贮藏温度、贮藏时间对猪肉糜氧化效应的影响。结果表明,贮藏时间和温度显著影响肉糜的氧化进程（p<0.05）,随贮藏时间的延长,酸价整体呈先上升后下降的趋势,而过氧化值、硫代巴比妥酸值整体呈上升趋势;贮藏温度越低,肉糜的AV值、POV值和TBARS值也越低,且变化缓慢。缩短贮藏时间和降低贮藏温度有利于控制肉糜脂肪氧化,研究表明,贮藏时间小于20d时效果最佳,30d时脂肪水解与氧化达到了动态平衡;-40℃贮藏效果最好,但从节能等角度综合考虑,-24℃更适合作为肉糜长期贮藏的温度。      

Effects of conjugated linoleic acid on color and lipid oxidation of beef patties during cold storage

The effects of conjugated linoleic acid (CLA) on color and lipid oxidation of beef patties were investigated. Ground beef was divided into three batches. The control patties were prepared with 90% lean meat and 10% tallow. The second treatment consisted of 90% lean meat with 9.5% tallow+0.5% CLA sources. The third treatment consisted of 90% lean meat with 8% tallow+2% CLA sources. The patties were wrap-packaged and then stored at 4° for 14 days. The CLA concentration significantly increased (P<0.05) by substituting CLA sources for fat. Storage of the patties did not alter the CLA concentration in beef patties. The treatment substituted with CLA sources had significantly lower TBARS (2-thiobarbituric acid-reactive substances) values (P<0.05) than the control. For oxymyoglobin contents and a* value, substituted CLA sources treatments had significantly higher values than the control. However, L* value significantly increased by substituting CLA sources for fat.     

Variability in temperature distribution and cooking properties of ground pork patties containing different fat level and with/without salt cooked by microwave energy

This study was carried out to evaluate the cooking effects of fat level (10% and 20%) with and without NaCl (1.5%) on the microwave cooking pattern and properties of ground pork patties. Each patty was cooked from a thawed state to 76.7°C in a microwave oven with full power (900W). Cooking rate in patties produced without salt was not affected by fat level, but the addition of salt in pork patties decreased cooking rate, regardless of fat levels. The temperatures at the edges of the patties increased faster than those at the center or the mid-way positions. In the patties with NaCl, the temperature of the center position was higher than that of the mid-way position. Patties containing salt within the same fat level had higher moisture content and lower fat content than those without salt, although no significant differences in compositional properties were observed between the center, midway, or edge positions. Total cooking loss, drip loss, and reduction in diameter and thickness were higher in patties with 20% fat compared to those with 10% fat, but the addition of salt resulted in reduction, regardless of fat level. Also, the addition of salt increased the redness and reduced yellowness of the cooked products.     

解冻方式对猪肉品质、理化性质与微观结构的影响

目的：探究冷冻猪肉最佳解冻方式。方法：考察了低频电场解冻、空气解冻、静水解冻3种解冻方式对解冻后猪肉的汁液损失率、水分含量、持水力、pH值、色差、挥发性盐基氮、菌落总数、质构特性、脂肪氧化和蛋白质氧化程度的影响。结果：低频电场解冻后汁液损失率（1.09%）、剪切力（2 600.15 N）、硫代巴比妥酸值（TBARS）增加量（62.50%）较低,色泽好,pH值接近鲜肉,蛋白质氧化程度较小,滋味物质丰富,对肉的微观结构破坏小,肌肉组织和肌纤维结构保持较好;静水解冻后菌落总数较少、对蛋白质氧化巯基值的影响较小。结论：低频电场解冻下猪肉的品质、理化性质与微观结构要优于其他两种解冻方式。     

Evaluation of physicochemical properties and microbial counts of raw and cooked low-fat patties added with eggplant powder prepared with different drying methods

Effects of different drying methods and different addition levels of eggplant (EP) on product quality of low-fat patties (LFPs) were investigated during storage. EP was dried in an oven dryer at 60 °C or a freeze dryer at −50 °C. LFPs were prepared by replacing with 1.5% soy protein isolate (SPI). Six treatments were used in this study: (1) control (CTL), without addition of EP; (2) reference (REF), 0.1% ascorbic acid; (3) O1, 0.25% oven-dried (OD) EP; (4) O2, 0.5% ODEP; (5) F1, 0.25% freeze-dried (FD) EP; and (6) F2, 0.5% FDEP. Redness (a*) and lightness (L*) values in LFPs added with EP were lower than those of others (p < 0.05) and decreased with increasing storage time. Yellowness (b*) values of cooked patties were increased during storage time (p < 0.05), with control having the highest value. The addition of EP or ascorbic acid into LFPs lowered microbial counts than control (p < 0.05). Thiobarbituric acid reactive substances (TBARS) was increased during storage, with REF having the lowest value, and patties added with EP had lower TBARS values than control during storage. Volatile basic nitrogen (VBN, mg%) contents of all patties also increased during storage time with O2 and F2 having lower values than control. Therefore, EP might have potential as a natural antioxidant in meat products during storage.     

光照对猪肉脂肪氧化影响的研究

研究了4±0.5℃贮存温度下,避光和光照条件对通脊肉肌内和皮下脂肪氧化程度的影响,同时比较9±1℃贮存温度下,不同光源(日光灯和白炽灯)照射对猪肉肌内脂肪氧化程度的影响。结果表明,无论是避光条件还是光照条件下,肌内脂肪氧化程度均远远大于皮下脂肪的氧化程度(p<0.05)。因此,控制肌内脂肪氧化是保证冷却肉良好品质的关键。光照可以明显加快脂肪氧化速度,并加深氧化程度,且对肌内脂肪氧化程度的加深远大于对皮下脂肪氧化程度的加深,同时研究发现,日光灯照射对脂肪氧化程度的加深远大于白炽灯照射对脂肪氧化程度的影响。     

Pork liver protein hydrolysates as extenders of pork patties shelf-life

The growing demand for the consumption of more natural products challenges the food industry to meet consumer expectations. In this regard, bioactive peptides obtained from flavourzyme, bromelain and alcalase activity were added to pork patties with the aim of improving their shelf-life. Five treatments were prepared: control (CON, without enzymatic extract), positive control (ASA, with 150 mg kg⁻¹ of ascorbic acid) and three batches with 250 mg kg⁻¹ of different porcine liver hydrolysates [flavourzyme (FLA), bromelain (BRO) and alcalase (ALC)]. The analysis of raw burgers included proximate composition (moisture, protein, fat and ash contents), colour parameters (L*, a*, b*), metmyoglobin, lipid oxidation, volatile compounds profile and sensory evaluation. Hydrolysate obtained from bromelain enzyme showed the best a* parameter (5.15), the least lipid oxidation (0.63 mg MDA kg⁻¹) and the lowest percentage of metmyoglobin (56.02%). Furthermore, this batch also presented the lowest content of aldehydes and alcohols resulting from lipid oxidation. Our results suggested that the hydrolysates obtained from bromelain activity possessed a good antioxidative activity, and therefore, they could be used as a natural antioxidant to extend the shelf-life of pork burgers.