Utilizing waste products from the food production and processing industries

Waste in the food industry is characterized by a high ratio of product-specific waste. Not only does this mean that the generation of this waste is unavoidable, but also that the amount and kind of waste produced, which consists primarily of the organic residue of processed raw materials, can scarcely be altered if the quality of the finished product is to remain consistent. The utilization and disposal of product-specific waste is difficult, due to its inadequate biological stability, potentially pathogenic nature, high water content, potential for rapid autoxidation, and high level of enzymatic activity. The diverse types of waste generated by various branches of the food industry can be quantified based on each branches' respective level of production. Moreover; the origins of each type of waste and a tabulated overview of the traditional agricultural methods for reusing the waste are discussed. Additionally, alternative methods of waste management have emerged, which target the most important contents of the waste. In conclusion, new possibilities for the utilization of food industry waste are described.     

Antioxidant activity of commercial food grade tannins exemplified in a wine model

Although commercial tannins are widely used in foods and beverages, an improved understanding of the structure and composition of vegetable tannins is needed to promote the exploitation of agri-food by-products and waste and their valorisation in more sustainable industrial applications. This study aims to characterise the phytochemical composition and antioxidant activity of 13 food grade tannins using multiple analytical approaches, including spectrophotometry and HPLC-ECD to determine the amount of targeted polyphenolic compounds. Moreover, the antioxidant activity of tannins was assessed in terms of radical scavenging activity (DPPH? assay), reducing power (FRAP assay), and redox properties (cyclic voltammetry, CV). A statistical univariate and multivariate correlation analysis was performed on 17 parameters including tannin content (range: 0.71–1.62 mM), gallic acid, (+)-catechin, syringic acid and (?)-epicatechin. The compositional profile of tannins was related to their chemical moiety, antioxidant activity and the botanical origin of the extracts. In particular, the CV signal at 500 mV was highly correlated with DPPH? value due to the catechol ring of flavonoids and trigalloyl moieties of gallic acid–based compounds. Practical examples of tannins application in winemaking are discussed.     

Antioxidant activity and physicochemical properties of chitosan films incorporated with Lycium barbarum fruit extract for active food packaging

Active packaging film was developed by incorporating Lycium barbarum fruit extract (LFE) into chitosan. The effects of LFE on physicochemical properties of the chitosan/LFE films were evaluated. When the weight ratio of LFE to chitosan was increased from 0:1 to 1:1, DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) free radical scavenging activity of the chitosan/LFE films increased near ten‐folds and reached up to 35.8%; water vapour permeability of the chitosan/LFE films decreased 43.0% from 5.67 g m mm^?2 day^?1 kPa^?1_, and water solubility decreased from 100% to 24.52% because of interactions between LFE and hydrophilic groups of chitosan confirmed by FTIR. However, the chitosan/LFE films became darker after LFE was incorporated. The pure chitosan film showed better tensile strength (23.19 MPa) and elongation at break (22.29%) than the chitosan/LFE films (15.52 MPa and 9.58% for the one with weight ratio of LFE to chitosan of 0.6:1).     

响应面法优化固态发酵餐厨垃圾与醋糟生产蛋白饲料

以餐厨垃圾和醋糟为原料,利用平菇、酿酒酵母、产朊假丝酵母和枯草芽孢杆菌进行固态发酵生产蛋白饲料.采用Design-Expert软件设计了Plackett-Burman筛选试验,从6个因素中筛选出3个显著因素分别为接种量、原料比和尿素添加量,再通过爬坡试验和响应面Box-Behnken设计对所选显著因素进行优化,得到最适确定最佳工艺条件为餐厨垃圾和醋糟添加质量比为67：33,接种量为10.46％,尿素添加量为2.9％,发酵产物真蛋白含量为24.04％.     

Antioxidant activity and consumer acceptance of grape seed flour‐containing food products

Grape seed flour (GSF) is produced from the pomace waste generated during winemaking. The inclusion of Merlot and Cabernet Sauvignon GSFs in cereal bars, pancakes and noodles was evaluated using antioxidant activity measurements [2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging]. Each product (noodles, pancakes and cereal bars) was also evaluated on separate days for consumer acceptance (n = 100 per panel). In comparing antioxidant activities, the highest DPPH radical‐scavenging activity was in pancakes containing Cabernet Sauvignon GSF (25% and 30%), noodles containing Cabernet Sauvignon GSF (20%) and cereal bars containing Merlot GSF (5%). From consumer sensory evaluation, cereal bars made with Merlot GSF, control pancakes and control noodles had high consumer acceptance. Products with low consumer acceptance included pancakes containing 25% Cabernet Sauvignon GSF and noodles containing 20% Cabernet Sauvignon GSF. Overall, the cereal bar containing 5% Merlot GSF showed a good balance of high antioxidant activity with consumer acceptability, making this a promising GSF‐containing new food product.     

Antioxidant activity of the essential oil and various extracts of Nepeta flavida Hub.-Mor. from Turkey

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil and various extracts (hexane, dichloromethane and methanol sub-fractions) of Nepeta flavida. GC and GC–MS analyses of the essential oil resulted in the identification of 68 compounds, representing 96.4% of the oil; 1,8-cineole (38.9%) and linalool (25.1%) were the main components, comprising 64.0% of the total oil. The samples were subjected to a screening for their possible antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, the IC₅₀ value of the N. flavida essential oil was determined to be 42.8 ± 2.19 μg/ml. Among the extracts, the strongest activity was exhibited by the polar sub-fraction of the methanol extract with an IC₅₀ value of 63.2 ± 1.75 μg/ml. In the β-carotene-linoleic acid system, N. flavida essential oil exhibited 86.3% ± 1.69 inhibition against linoleic acid oxidation. Among the extracts prepared with various solvents, a correlation was observed between the polarity and antioxidant activity. The extracts exhibited the same activity pattern in this system the most active one is the polar sub-fraction, 79.7% ± 0.89. On the other hand, 1,8-cineole, a major compound of the essential oil, exhibited marked antioxidant activity in both systems, whereas the other compound, linalool, did not show any activity. The amount of total phenolics was highest in the polar and non-polar sub-fractions. Particularly, a positive correlation was observed between the total phenolic content and the antioxidant activity of the extracts. As estimated from the results, amounts of phenolic compounds were less in hexane and dichloromethane extracts than in the others. In conclusion, antioxidant potentials of polar and non-polar methanol sub-fractions could be attributed to their high phenolic contents. In both systems, antioxidant capacities of BHT, ascorbic acid, curcumin and α-tocopherol were also determined in parallel experiments.     

Antioxidant activity of ethanol and petroleum ether extracts from Brazilian propolis

Antioxidant activities of ethanol and petroleum ether extracts from Brazilian propolis were determined by α,α-diphenyl-β-picrylhydrazyl (DPPH) radical-scavenging and ferric thiocyanate (FTC) methods, using α-tocopherol and butylated hydroxytoluene (BHT) as references. The DPPH assay showed that ethanol extract possessed significantly higher activity compared with BHT and petroleum ether extract but lower than that of α-tocopherol. Results from the FTC assay indicated that the activity of ethanol extract was higher than that of α-tocopherol and petroleum ether extract but lower than BHT. Basically, this antioxidant activity was dose-dependent and ethanol extract exhibited higher activity than that of petroleum ether extract at the same concentration. Additionally, the chemical constituents of propolis were determined, and results showed that the propolis contained high content of antioxidant compositions, such as flavonoids (73.00 g kg⁻¹), total phenolic compounds (134.40 g kg⁻¹), and Vitamin E (0.16 g kg⁻¹), which contributed greatly to its strong antioxidant activity.     

Antioxidant and free radical-scavenging activities of phenolic extracts of olive fruits

The antioxidant ability of phenolic extracts of olive fruits during maturity in Chondrolia and Amfissis cultivars grown at 10 m and 300 m altitude showed that altitude affected phenol content, antioxidant and Fe²⁺/Fe³⁺ reduction/binding ability. The hydroxyl radical, peroxyl radical and peroxynitrite-induced DNA nicking assays have been used to evaluate the anti-radical activity of the extracts. Results showed that the ability of olive extracts to prevent radical-mediated DNA damage arises from the triple synergistic action of the genotype, the altitude and the maturation stage.     

Bioutilisation of agro‐industrial waste for lactic acid production

With the advancement in science and technology, the importance of bioconversion of industrial waste into value‐added products through biotechnological route has been realised. Moreover, to make the process economic and environment responsive, agro‐industrial waste/by‐products can be used as substrates in fermentation processes as an inexpensive raw material. In the field of food biotechnology, organic acids represent the third largest category among the biological products, which can be produced chemically or by fermentation process. Among organic acids, lactic acid holds an important position because of its multivariate applications in food, pharmaceutical, cosmetics, textiles and other industries. Traditionally, lactic acid was produced from pure substrates, but agricultural feedstocks and industrial by‐products have evoked the interest of researchers to use them as raw materials for the biotechnological production of lactic acid. The utilisation of biomass has gained major attention due to environmental hazards, scarcity of fossil fuels and meet the increasing world food and feed demand. Integrated biorefinery approaches have also been adopted for the production of lactic acid along with primary product to minimise the cost. This review provides comprehensive information on the recent advances in biotechnological production of lactic acid utilising agro‐industrial waste/by‐products.     

Phenolic acid profiles and antioxidant activities of wheat bran extracts and the effect of hydrolysis conditions

Four different types of wheat bran were extracted and analyzed for phenolic acids using the Folin–Ciocalteu method and HPLC. The extracts and their hydrolysis products were also evaluated for their antioxidant activities. The total phenolic content of the red wheat bran was higher than that of the white wheat. We found that the majority of the phenolic acids existed in a bound form in wheat bran. These phenolic acids can be released by hydrolyzing the bran under alkaline or acidic conditions; however, the former was more efficient in the release of free phenolic acids than the latter. Ferulic, vanillic, and syringic acids were the major individual phenolic acids in the studied wheat bran. The main portion of the total ferulic acid was from alkaline hydrolysis. The alkaline hydrolysable fractions had greater antioxidant activities, while the acid hydrolysable fractions showed lower activities in both the red and white bran. The antioxidant activity of bran extract was stronger than that of free phenolic acids.     

Antioxidant activity of protein extracts from heat-treated or thermally processed chickpeas and white beans

In this study, antioxidant activities of water-soluble protein extracts from chickpeas and white beans were investigated. The area under the curve (AUC) values of lyophilized crude protein extracts (dialyzed or undialyzed) from thermally processed (121 °C for 20 min) or heat-treated (90 °C for 20 min) chickpeas (73–91 μmol trolox/g) and white beans (39–67 μmol trolox/g) indicated a higher free radical-scavenging capacity and thermostability for chickpea proteins than for white bean proteins. The thermal processing also increased the Fe⁺²-chelating capacity of lyophilized chickpea crude protein extracts 1.8-fold whereas it caused a 2.3-fold reduction in the Fe⁺²-chelating capacity of lyophilized white bean crude protein extracts. Dialysis increased the protein content of lyophilized chickpea extracts 1.5–2-fold but it did not affect the protein content of lyophilized white bean extracts significantly. Ammonium sulfate precipitation was not effective for selective precipitation of antioxidant proteins. However, it improved the free radical-scavenging capacity of lyophilized protein extracts from thermally processed chickpeas and white beans by almost 25% and 100%, respectively. DEAE-cellulose chromatography, indicated the presence of five (A₁–A₅) and three (B₁–B₃) antioxidant protein fractions in heat-treated and thermally processed chickpea protein extracts, respectively, and can be used for the partial purification of antioxidant proteins. The results of this study showed the good potential of chickpea proteins as thermostable natural food antioxidants.     

Antioxidant activity of Rhizoma Smilacis Glabrae extracts and its key constituent-astilbin

Rhizoma Smilacis Glabrae is widely consumed by Chinese as functional food and in folk medicine for its medicinal properties. In this study, methanol and water extracts of Rhizoma Smilacis Glabrae were prepared. The water extract was further divided into polysaccharide and supernatant fractions. Constituents in different extracts were analysed by capillary electrophoresis, and levels of total phenolics were also determined using the Folin-Ciocalteu method. Astilbin, the main constituent in the herb, was isolated and purified. Different antioxidant tests were employed to evaluate the antioxidant activities of the extracts and the isolated astilbin, and the results were compared with two commonly used synthetic antioxidants-butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Methanol, water extract and supernatant fraction showed concentration dependent antioxidant activity while polysaccharide didn’t show any antioxidant activity. Purified astilbin showed the strongest antioxidant activity in comparison to any other extracts.     

Antioxidant capacities of Gundelia tournefortii L. extracts and inhibition on glutathione-S-transferase activity

Gundelia tournefortii L. is an important food source and a well-known medicinal plant in Eastern Anatolia. Therapeutic effects of medicinal plants are known to be closely related to their antioxidant capacities. Antioxidant activities of G. tournefortii, both for the aerial parts and seeds, were investigated by using both 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and lipid peroxidation inhibition methods. The seeds were found to have higher antioxidant potential than the aerial, with IC₅₀ values of 0.073 mg/mL for DPPH scavenging and 0.146 mg/mL for lipid peroxidation inhibition capacities. In addition, total phenolic contents of the Gundelia tournefortii L. extracts, especially the seed extracts correlates to its high antioxidant activity with 105.1 ± 8.7 μg gallic acid equivalents (GAEs) per mg of seed extract. Plant extracts with high phenolics content are known to have important effects on various enzymes, as well as glutathione-S-transferases, which are important detoxification enzymes in phase II systems with an important role in developing multi-drug resistance to chemotherapy in tumour cells. Consequently, the effects of G. tournefortii extracts on crude cytosolic glutathione-S-transferase was also studied and the seed extracts have shown effective inhibition of cytosolic GST activity, with an IC₅₀ of 97.51 μg/mL.     

正确审视食品添加剂功与过

简述常规几种食品添加剂的功用,阐述它在国民经济及食品工业发展中的重要意义,纠正几个关于食品添加剂的错误观念,并浅谈食品添加剂的发展方向。     

Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolic extracts as influenced by genotype and ethanol concentration

Ethanolic extracts prepared from the fruits of three cultivars of black currant (‘Record’, ‘Blackdown’ and ‘Ronix’) macerated in three concentrations (40%, 60% and 96%) of aqueous ethanol were investigated for their anthocyanins profile, total phenolics and antioxidant activity.     

Antioxidant activity and proline content of leaf extracts from Dorystoechas hastata

Dorystoechas hastata (D. hastata) is a monotypic plant endemic to Antalya province of Turkey. D. hastata leaves are used to make a tea locally called “çalba tea”. Diethyl ether (E), ethanol (A), and water (W) were used for the sequential preparation of extracts from dried D. hastata leaves. A hot water extract (S) was also prepared by directly boiling the powdered plant in water. The antioxidant activities of the extracts were tested by ferric thiocyanate (FTC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods. E extract exhibited the greatest antioxidant activity with FTC method, whereas S extract exhibited the lowest IC₅₀ value (6.17 ± 0.53 μg/ml) for DPPH radical scavenging activity. Total phenolic contents of the extracts were estimated by Folin–Ciocalteu method and S extract was found to contain the highest amount (554.17 ± 20.83 mg GAE/g extract) of phenolics. Extract A contained highest flavonoid content and there was a inverse linear correlation (R² = 0.926) between IC₅₀ values for DPPH radical scavenging activity and flavonoid contents of all extracts. Reducing power of extracts increased in a concentration-dependent manner. S extract was found to possess higher reducing power than equivalent amount of ascorbic acid at 20 and 25 μg/ml concentrations. Linear correlation between reducing power and concentration of E, A, and W extracts (R² > 0.95) was observed. A, W, and S extracts contained relatively high levels of proline. The results presented suggest that D. hastata may provide a natural source of antioxidants and proline.     

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.     

Screening of some Algerian medicinal plants for the phenolic compounds and their antioxidant activity

Since recent times, there is a growing interest in the food industry and in preventive health care for the development and evaluation of natural antioxidants from medicinal plant materials. In the present work we have investigated the antioxidant potency of phenolic compounds of 11 indigenous wild plant species from the Algerian Atlas commonly used in Arab folk medicine for a wide range of conditions. The antioxidant activity of each phenolic extracts has been assessed by using the Trolox Equivalent Antioxidant Capacity (TEAC) as a chemical test, and in a dynamic way by a biological assay based on whole blood resistance to free radical aggression. Of the 11 tested plants, 2 showed prominent antioxidant activity: Anthemis arvensis and Artemisia campestris. These plants had a very high level of Trolox equivalents and induced a strong delay of free radical-induced red blood cells hemolysis compared to antioxidant references. Artemisia campestris was the best inhibitor, its effect was far stronger than that of caffeic acid and was more than three times as high as ascorbic acid and two times higher than α-tocopherol efficiency. HPLC analysis showed a good correlation between the antioxidant activity and hydroxycinnamic derivatives. These preliminary results on the in vitro protection of blood against oxidative stress emphasized the benefit of the phenolic compounds of these medicinal plants. Our results enable us to proceed towards more detailed chemical and pharmacological understanding of these plant materials and show the interest of natural antioxidant in medicinal plants for the prevention of much free radical-mediated pathology.     

Characterisation of phenolic acids,flavonoids, proanthocyanidins and antioxidant activity of water extracts from seed coats of marama bean [Tylosema esculentum] – an underutilised food legume

Freeze‐dried aqueous phenolic extracts with possible application as natural antioxidant functional food ingredients were prepared from marama bean seed coats by extracting with water. Phenolic acids, flavonoids and proanthocyanidins in the extracts were characterised by HPLC/MS. The major flavonoids were the flavanols methyl (epi)afzelechin‐3‐O‐gallate (40%) and methyl (epi)catechin‐3‐O‐gallate (28%), and the major phenolic acid was gallic acid (10%). Proanthocyanidins in the extracts were predominantly prodelphinidins composed of epicatechin‐3‐O‐gallate and epigallocatechin present as major terminal and extension units and epigallocatechin‐3‐O‐gallate and epicatechin present as minor extension unit constituents. The polymer structure was found to be unique compared with other legumes because of the high percentage of galloylated units. Extracts showed a high DPPH free radical scavenging activity (707 μmol TE g^?1), protective effect against AAPH‐induced human red blood cell haemolysis and copper‐catalysed human LDL oxidation suggesting that the extracts may have potential health benefits.