Processing of Apple Pomace for Bioactive Molecules

The growth of horticulture industries worldwide has generated huge quantities of fruit wastes (25%–40% of the total fruits processed). These residues are generally a good source of carbohydrates, especially cell wall polysaccharides and other functionally important bioactive molecules such as proteins, vitamins, minerals and natural antioxidants. “Apple pomace” is a left-over solid biomass with a high moisture content, obtained as a by-product during the processing of apple fruits for juice, cider or wine preparation. Owing to the high carbohydrate content, apple pomace is used as a substrate in a number of microbial processes for the production of organic acids, enzymes, single cell protein, ethanol, low alcoholic drinks and pigments. Recent research trends reveal that there is an increase in the utilization of apple pomace as a food processing residue for the extraction of value added products such as dietary fibre, protein, natural antioxidants, biopolymers, pigments and compounds with unique properties. However, the central dogma is still the stability, safety and economic feasibility of the process(s)/product(s) developed. This review is mainly focused on assessing recent research developments in extraction, isolation and characterization of bioactive molecules from apple pomace, along with their commercial utilization, in food fortification.     

Protein enrichment of apple pomace by co-culture of cellulolytic moulds and yeasts

The co-culture of cellulolytic moulds and yeasts on apple pomace in solid-state fermentation (SSF) and liquid-state fermentation (LSF) increased the protein content of apple pomace. The co-culture of Candida utilis and Aspergillus niger was the best among several combinations and increased the protein content of dried and pectin-extracted apple pomace to 20% and 17%, respectively, under SSF conditions.The authors are with the Microbiology Research Laboratory, Department of Biosciences, Himachal Pradesh University, Shimia-171005, India.     

Optimization of production conditions for β-mannanase using apple pomace as raw material in solid-state fermentation

Apple pomace is a wasted resource produced in China in large quantities, disposal of which has caused serious environmental problems. In order to make the best of this residue, apple pomace together with cottonseed powder was used as a raw material to produce β-mannanase in solid-state fermentation (SSF) by Aspergillus niger SN-09. Optimization of fermentation conditions for maximizing β-mannanase production was carried out using Plackett-Burman and Central Composite designs. A mixture of apple pomace and cottonseed powder (3:2, w/w) with 59.2 % (w/w) initial moisture, together with certain ionic compounds and salts, proved to be the optimal medium. The test fungi were inoculated in the optimized medium and incubated at 30°C for 48 h. The activity of β-mannanase reached 561.3 U/g, an increase of 45.7 % compared with that in basal medium, and reached the same level of production as that achieved using wheat bran and soybean meal as raw materials as in most factories in China. This is the first report of the use of apple pomace as a raw material to produce β-mannanase in SSF. This will not only reduce the production cost of β-mannanase, but also represents a new and effective way to make the best use of apple pomace, which can consequently help to reduce the environmental pollution caused by this waste.     

固态发酵技术提高苹果渣附加值的应用研究

能源危机和苹果渣带来的环境问题促进了固态发酵技术的发展.相对于液体深层发酵,固态发酵在生产中具有处理量大,操作简单,成本低等独特的优势.综述了以苹果渣为原料利用固态发酵技术生产酶制剂、柠檬酸、酒精和蛋白饲料等的研究应用进展,以及存在的问题和前景展望.     

Influence of pectinase treatment on fruit spirits from apple mash, juice and pomace

The current investigation was conducted to determine the influence of pectinase treatment on fruit spirits produced from apple mash, juice, and pomace. Crispin apples were processed into apple mash, juice, and pomace in our pilot-plant, and fermented with a commercial Red Star wine yeast (Sachharomyces cerevisiae Davis 904). After fermentation, the samples of fermented apple mash, juice, and pomace were distilled, and the distillates were analyzed by HPLC with a Bio-Rad Aminex HPX 87H column and a refractive index detector. Methanol, ethanol, n-propanol, iso-butanol, and iso-amyl alcohol were identified as the major alcohols in all the apple spirits. Student's t-test results indicate that there are significant differences between the methanol concentrations of pectinase treated and non-pectinase treated apple spirits. Duncan's multiple range tests show significant differences in the concentrations of methanol of the fruit spirits made from apple mash, juice, and pomace. Apple pomace yielded significantly higher methanol concentrations than apple mash and juice. Pectinase treatment had little effect on the concentrations of n-propanol, iso-butanol, and iso-amyl alcohol. It is concluded that fruit spirits made from the pectinase treated mash, juice, and pomace of Crispin apples had methanol concentrations significantly above the United States FDA guidance of 0.35% by volume or 280 mg/100 mL of fruit brandy containing 40% ethanol.     

黑曲霉固态发酵苹果渣产β-甘露聚糖酶的工艺优化

目的:对黑曲霉SL-08固态发酵苹果渣生产β-甘露聚糖酶的生产工艺进行优化,旨在探寻苹果渣的综合利用方式,降低β-甘露聚糖酶的生产成本。方法:采用Plackett-Burman试验设计和响应面法进行优化。结果:最佳培养基组成为苹果渣与棉粕1∶1(w/w)、尿素2%(w/w)、KH2PO40.1%(w/w)、初始含水率59%(w/w)、CaCl20.2%(w/w)、MgCl20.1%(w/w),30℃恒温培养48h,β-甘露聚糖酶酶活力可达539U/g干曲,比基础培养基提高了28.3%,达到了以豆粕与麸皮为生产原料时的产酶水平。结论:采用黑曲霉SL-08对苹果渣进行固态发酵是一种有效的生物转化方式,既可用于β-甘露聚糖酶的生产,取代豆粕与麸皮等常规原料,降低生产成本;也可以对苹果渣进行综合利用。     

苹果渣乙醇提取物抗菌活性及防腐作用研究

为提高苹果渣资源利用率,探究苹果渣乙醇提取物的抗菌活性和防腐性能,该文采用微波辅助提取法制取苹果渣乙醇提取物,用抑菌圈实验测定其抗菌活性,并研究了其防腐作用.结果表明:(1)苹果渣乙醇提取物对酵母菌抑制作用不明显(抑菌圈直径<1 mm),对金黄色葡萄球菌和大肠杆菌的抑菌作用较明显(抑菌圈直径为6～9 mm),最佳抑菌浓...     

Pectin—Its extraction and utilization

This cementing substance between the cells of all plants is economically valuable as a jellifying, stabilizing, emulsifying and binding agent, and is extracted for those purposes principally from apple pomace and citrus peels.     

Generation of antitumor active neutral medium-sized alpha-glycan in apple vinegar fermentation

The physiologically active substances in apple vinegar have not yet been chemically characterized. We studied the biological functions of apple vinegar produced from crushed apples, and found that the constituent neutral medium-sized alpha-glycan (NMalphaG) acts as an antitumor agent against experimental mouse tumors. NMalphaG is a homoglycan composed of glucose having a molecular weight of about 10,000 and a branched structure bearing alpha (1-4,6) linkages.In this study, we clarified the origin of NMalphaG in apple vinegar by examination of its content in alcohol and acetic acid fermentation products sequentially. We found that NMalphaG appeared in acetic acid fermentation, but not in alcohol fermentation. Furthermore we investigated NMalphaG origin using acetic acid fermentation from alcohol fortifiied apple without alcohol fermentation and from raw material with varying amounts of pomace. The results indicate that NMalphaG originated in the apple fruit body and that its production requires both fermentation processes.     

Bacterial cellulose synthesized with apple pomace enhanced by ionic liquid pretreatment

Abstract

Apple pomace was explored as alternative feedstock for producing bacterial cellulose (BC) by Gluconacetobacter xylinus following a cellulase saccharification performed after pretreatment of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). The dissolving process of apple pomace cellulose was observed by polarized light microscopy (PLM). As FT-IR and XRD results demonstrated, the IL pretreatment proved to be a physical process and no changes in the crystalline structure occurred during the pretreatment. However, the SEM result showed that more fissures and breakages appeared on the surface of pomace microfibers after IL-pretreating, which increased the contact area with cellulase and improved the enzymatic hydrolysis efficiency. An enhancing effect on the BC yield has been observed, 27% higher yield of BC obtained from hydrolysate as compared to sucrose-based medium indicates efficiency of IL-treated apple pomace to serve as high quality feedstock in BC production.     

Production of Alcohol from Apple Pomace

Production of ethyl alcohol from apple pomace with a Montrachet strain of Saccharomyces cerevisiae is described. More than 43 g of the ethyl alcohol could be produced per kg of apple pomace fermented at 30°C in 24 h. The fermentation efficiency of this process was approximately 89%.     

Generation of Antitumor Active Neutral Medium-Sized α-Glycan in Apple Vinegar Fermentation

The physiologically active substances in apple vinegar have not yet been chemically characterized. We studied the biological functions of apple vinegar produced from crushed apples, and found that the constituent neutral medium-sized α-glycan (NMαG) acts as an antitumor agent against experimental mouse tumors. NMαG is a homoglycan composed of glucose having a molecular weight of about 10,000 and a branched structure bearing α (1-4,6) linkages.

In this study, we clarified the origin of NMαG in apple vinegar by examination of its content in alcohol and acetic acid fermentation products sequentially. We found that NMαG appeared in acetic acid fermentation, but not in alcohol fermentation. Furthermore we investigated NMαG origin using acetic acid fermentation from alcohol fortifiied apple without alcohol fermentation and from raw material with varying amounts of pomace. The results indicate that NMαG originated in the apple fruit body and that its production requires both fermentation processes.     

Butanol production from apple pomace

Summary The use of apple pomace for butanol production was studied by employing strains ofClostridium acetobutylicum andbutylicum. Yields of butanol between 1.9 and 2.2 % of fresh apple pomace are reported.     

Solid-substrate fermentation ofKloeckera apiculata andCandida utilis on apple pomace to produce an improved stock-feed

Apple pomace was used in solid-substrate fermentation with the yeastsKloeckera apiculata orCandida utilis Y15. A total crude protein content of 7.5% (w/w) was achieved after 72 h for each yeast. The concentration of essential amino acids in the modified apple pomace was more than twice that in the control, enhancing its nutritive value as a stock-feed supplement. The fermentation of pomace as described can be used to reprocess this waste material into a useful value-added product for the agricultural sector.H. Rahmat was and R.A. Hodge, G.J. Manderson and P.L. Yu are with the Biotechnology Group, Department of Process and Environmental Technology, Massey University, Palmerston North, New Zealand; H. Rahmat is now with the Department of Chemical Engineering, Queen's University of Belfast, Belfast BT9 5AG, Northern Ireland, UK.     

Bioconversion of apple pomace into a nutritionally enriched substrate by Candida utilis and Pleurotus ostreatus

Apple production in the world has increased significantly over the last 10 years. A considerable fraction of these fruits, mainly those not approved for fresh consumption, is industrially processed to produce juices, flavours and concentrates. During this processing, a large amount of solid residues is produced, comprised mainly of peels, seeds, and pulp, which are collectively known as apple pomace. This work aims to select biological treatments and conditions for the bioconversion of apple pomace by Candida utilis and Pleurotus ostreatus, either individually or sequentially, into an enriched substrate with increased digestibility for use as ruminant feed. After C. utilis fermentation, the protein level increased 100% and the mineral content 60%, accompanied by 8.2% of increase in the digestibility. The level of free sugars decreased 97% after substrate supplementation with ammonium sulphate (10 g l^–1). After optimization, sequential fermentation with C. utilis and P. ostreatus achieved a high protein level with 500% of crude protein enrichment after 60 days of fermentation as well as a considerable increase in the mineral level. The level of free sugars increased after the fermentation with P. ostreatus alone due to pectin and hemicellulose degradation. Considering the time required for fermentation, the C. utilis treatment was the most efficient treatment to convert apple pomace into a more nutritive substrate for ruminant feed.     

Dietary fiber-rich colloids from apple pomace extraction juices do not affect food intake and blood serum lipid levels, but enhance fecal excretion of steroids in rats

The aim of this study was to investigate the effects of colloids isolated from apple pomace extraction juices (so-called B-juices) produced by enzymatic liquefaction on food intake, levels of blood serum lipids, and fecal excretion of bile acids (BA) and neutral sterols (NS) in vivo. Ten male Wistar rats per group were fed diets containing either no apple dietary fiber (DF) (control), a 5% supplementation with juice colloids, or an alcohol-insoluble substance (AIS) from apples for 6 weeks. Apple DF in diets led to lower weight gain in rats fed with B-juice colloids (P< 0.05). For these rats, food intake was not affected but was highest with feeding AIS (10% more than control) to cover energy requirements. The supplementation of diet with apple DF from extraction juices or AIS had minor effects on blood serum lipids. In rats fed either juice colloids or AIS, up to 30% (5.31 micromol/g dry weight) and 88% (7.69 micromol/g dry weight) more primary BA were excreted in feces, respectively, as compared to that in the control group (4.10 micromol/g dry weight) (P < 0.05). In cecal contents, a 15% (juice colloids) to 37% (AIS) increase in primary BA was found. In contrast, concentrations of secondary BA were lower in feces of test groups (P < 0.05). Excretion of total BA and NS was higher in rats fed apple DF (P < 0.05). Our study is the first to prove that there are beneficial physiologic effects of apple DF isolated from pomace extraction juices produced by enzymatic liquefaction. These results may help to develop such innovative juice products that are rich in DF of fruit origin for diminishing the lack of DF intake.     

Immobilization of co-culture of Saccharomyces cerevisiae and Scheffersomyces stipitis in sodium alginate for bioethanol production using hydrolysate of apple pomace under separate hydrolysis and fermentation

Apple pomace as a substrate for bioethanol production is interesting due to its abundance and sustainable availability in varied states like Himachal Pradesh (H.P.), Jammu and Kashmir, Uttarakhand and Arunachal Pradesh, India. In the current study, apple pomace which is the main fruit industrial waste of H.P. was evaluated as feedstock for bioethanol production by the process of enzymatic saccharification using multiple carbohydrases. Microwave pretreatment of the apple pomace resulted in the efficient removal of lignin and crystalline structure of cellulose fibre. The enzymatic saccharification of the pretreated biomass was done by optimizing parameters for maximal saccharification leads to production of 27.50?mg/g of reduce, ng sugar. An enhanced ethanol yield of 44.46?g/l and fermentation efficiency of 58% by immobilized co-culture of Saccharomyces cerevisiae MTCC 3089 and Scheffersomyces stipitis NCIM 3498 under SHF as compared to fermentation performed with free yeast cells, i.e. 34.46?g/l of ethanol and 45% of fermentation efficiency.     

单细胞蛋白生产最佳接种混合比的研究*

以苹果渣混合菌发酵生产单细胞蛋白为例,利用3个和4个菌种分别探讨了多菌种发酵最佳接种混合比的选取问题,获得一种求取最佳接种混合比的有效方法,完善了发酵生产单细胞蛋白这类问题的研究。     

Apple pomace: A potential substrate for citric acid production by Aspergillus niger

Summary Apple pomace was used as a fsubstrate for citric acid production by five strains of Aspergillus niger. A. niger NRRL 567 produced the greatest amount of citric acid from apple pomace in the presence of 4% methanol. The yield was 88% based on the amount of sugar consumed.     

A simple device for controlled feeding of pasty materials used as fermentation substrates

Summary A simple device is described for con-trolled feeding of pasty materials in laboratory scale fed-batch cultures. The device was tested with apple pomace as raw material for production of microbial biomass, using the level of dissolved oxygen as controlled parameter.