Article

The effect of enzymatic processing on banana juice and wine

Article

The effect of enzymatic processing on banana juice and wine

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Abstract

Although bananas are widely grown worldwide in many tropical and a few subtropical countries, banana beverages are still among the fruit beverages processed by use of rudimentary methods such as the use of feet or/and spear grass to extract juice. Because banana juice and beer remained on a home made basis, there is a research drive to come up with modern technologies to more effectively process bananas and to make acceptable banana juices and wines. One of the main hindrances in the production of highly desirable beverages is the pectinaceous nature of the banana fruit, which makes juice extraction and clarification very difficult. Commercial enzyme applications seem to be the major way forward in solving processing problems in order to improve banana juice and wine quality. The particular pectinolytic enzymes that were selected for this study are Rapidase CB, Rapidase TF, Rapidase X-press and OE-Lallzyme. In addition this study, investigate the applicability of recombinant yeast strains with pectinolytic, xylanolytic, glucanolytic and amylolytic activities in degrading the banana polysaccharides (pectin, xylan, glucan starch) for juice and wine extraction and product clarification. The overall objective of this research was to improve banana juice and wine by enzymatic processing techniques and to improve alcoholic fermentation and to produce limpid and shelf-stable products of clarified juice and wine. The focus was on applying the selected commercial enzyme preparations specifically for the production of better clarified banana juice and wine. This is because the turbid banana juice and beer, which contain suspended solids that are characterised by a very intense banana flavour, require a holistic approach to address challenges and opportunities in order to process pure banana beverages with desirable organoleptic qualities. The specific objectives of applying commercial enzymes in the processing of banana juice and wine, comparing with grape winemaking practices, use of recombinant yeast and analyses of various parameters in the juices and wines made have enabled generation of information that could be of help to prospective banana juice and wine processors. The research findings obtained could be used to establish a pilot plant or small-scale industry in the banana processing beverages producing large quantities,and finally the overall objective of obtaining limpid and shelf stable products would be achieved. Thesis (PhD (Viticulture and Oenology. Wine Biotechnology))--University of Stellenbosch, 2008.

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... However, banana beer is believed to have been produced after the domestication of brewing-banana cultivars into Africa. The processing of juice, from matured, green beer-bananas, for alcoholic beverages was noted to be themain characteristic feature of East African countries, such as Rwanda, Uganda, Burundi, Kenya, Tanzania and Eastern Congo, where the majority of farmers in these banana-growing regions (East African highlands) mainly cultivate banana juiceyielding cultivars (Kyamuhangire et al., 2002;Byarugaba-Bazirake, 2008;Aurore et al., 2009) as compared to the rest of the world. In addition, Palmer (1971), quoted Baker and Grant (1864 and 1886), who described the processing of banana beer in the Kagera region (currently Tanzania) and in West-Central Uganda. ...
... Production of traditional banana beer serves as an important source of income and employment among many farmers. Processing this traditional banana beer employs rudimentary methods, such as the use of feet, hands and spear grass to extract juice (Kyamuhangire et al., 2002;Byarugaba-Bazirake, 2008) (Figure 1A and B). Its production has remained mainly by home-based brewers in rural areas. ...
... Its production has remained mainly by home-based brewers in rural areas. Although the traditional methods are still preferred, improved processing techniques are indispensable to add value to beer products, particularly banana beverages, which still pose processing challenges in Rwanda and many other developing countries (Byarugaba-Bazirake, 2008;Mukantwali et al., 2008;Lues et al., 2011). ...
Article
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Indigenous traditional beers play an important role in the daily social, economic, nutritional and cultural life of the people especially in developing countries. Bananas and banana beer remain very popular in Rwanda and they continue to be an important source of income. Banana cultivation forms an essential part of the socio-economic life of Rwandan communities, and the fruit has a long and widespread history in the production of alcoholic beverages. However, there is very little documentation on this product. Although, methods of manufacture have been passed through generations in Rwanda, little is reported in the literature, and research has been minimal. As a result of increased rural-urban migration, and the adoption of Western culture by the younger generation, most of these fermentation techniques will die off, and remain history to the next generation while many other countries are expanding and scaling up the processing of their respective indigenous fermented foods and beverages. Therefore, the objective of this mini-review was to document the traditional processing techniques, characteristics of the product, traditional culture associated with this beverage and to trace its origin and the problems which farmers might be facing during processing in order to identify research topics that can alleviate some of the problems and constraints identified.
... A number of methods for obtaining low-viscosity clear banana juice such as enzymatic maceration of ripe banana pulp, hot water extraction, as well as a combination of the two have been investigated (Lee et al., 2006;Surendranathan et al., 2003;Minatchy et al., 2007). In most cases banana juice extracted using enzymatic or hot water extraction methods is cloudy, and the processes are expensive due to high cost of enzymes and energy requirement (Byarugaba-Bazirake, 2008;Kyamuhangire et al., 2002; *Corresponding author. E-mail: kibazohi@yahoo.com, ...
... In both cases, mechanical juice extractors were employed. Juice yield was comparable to 55.6 to 64.8% (w/w) for juice produced by mechanical and enzymatic method from Pisang Awak (Kyamuhangire et al., 2002;Byarugaba-Bazirake, 2008). ...
Article
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Low-viscosity clear banana juice is traditionally produced using a rudimentary mechanical process of kneading a mixture of ripe high-tannin banana and grass. The aim of this study was to come up with a new efficient and hygienic process that does not require use of grass. According to a new process, peeled ripe high-tannin Pisang Awak banana fingers were mashed in a blender, without addition of grass, until pulp agglomeration occurred. The mashed pulp was pressed to separate clear banana juice. The process successfully produced clear banana juice with low-viscosity (1.85 × 10-3 Pa.s), high content of dissolved solids (27-28°Brix), and average density of 1120 kg.m-3. Juice yield increased with mashing time up to 60% (w/w), and degree of ripeness until fruit colour was mostly yellow, but juice extraction failed for overripe banana. Condensed tannins decreased with ripening and juice extraction was possible as long as condensed tannin concentration was above 0.68% (w/w) of peeled banana. Therefore, low-viscosity clear banana juice can be produced in a more hygienic condition using the new process.
... Several investigators have reported the influence of pectinase enzyme treatment on the methanol concentrations of wines. 3,6,7 As for glycine, this can be from sugar cane juice or yeast extract, which is one element of the medium for Saccharomyces cerevisiae. Glycine first generates methylamine by glycine decarboxylase, then reacts with nitrous acid to produce methanol. ...
... Several investigators reported the influence of pectinase enzyme treatment on the methanol concentrations of wines. 3,7,18 In this study, it was also found that pectinase and cellulose significantly increased the methanol levels of sugar cane spirits (Fig. 4). It has been reported that the high methanol content is ascribed to the use of pectinase, which is commonly used in mango wine production and is responsible for the splitting of pectic substances to galacturonic acid and methanol. ...
Article
BACKGROUND To decrease the methanol content of the sugar cane sprits, mutagenesis of ultraviolet (UV) coupled with diethyl sulfate (DES) was used to generate a mutant of Saccharomyces cerevisiae with lower methanol content. Meanwhile, the effects of the additions of pectinase, cellulase and glycine on the production of methanol in sugar cane spirits were evaluated.RESULTSAfter mutagenesis of UV coupled with DES, a mutant S. cerevisiae DU9 with low production of methanol (97.3 ± 1.7 mg/L) was selected, with a 12.3% decrease of that of S. cerevisiae D4 only with DES treatment, and with a 27.8% reduction of that of the strain without any treatment. Pectinase and cellulase significantly increased the methanol levels of the sugar cane spirits. The results showed that there was linear relationship between glycine (concentration within 0∼0.9 g/L) and methanol in sugar cane sprits and the linear equation was y = 104.7 × −4.79 with the conversion rate of glycine conversion to methanol as 24.56%.CONCLUSION Mutagenesis of UV coupled with DES is an efficient way to generate a mutant of S. cerevisiae with lower methanol content. Also, it is necessary to control the additions of pectinase, cellulase and glycine in the fermentation medium, and other unknown ways to generate methanol metabolic pathway in yeasts may need further study. © 2014 Society of Chemical Industry
... Furthermore, the extraction of sugars and other soluble components from the pulp (fruit flesh) can be difficult and inefficient (1). Mechanical chopped fruit can be further subjected to thermal and/or enzymatic treatments (2). ...
... Beside pectinases, cellulases and hemicellulases are used but their application is much less frequent (3). The activity of pectolytic enzymes during the processing of fruit intended for wine production not only is linked to the hydrolysis of pectin, which leads to the liquefaction of pomace and an increase in the wine yield and facilitates clarification and filtration, but also leads to a significant increase in the efficiency of extraction of the coloured and aromatic fruit substances (2,3). Commercial preparations of pectolytic enzymes usually represent a mixture of polygalacturonase, pectin lyase and pectin methyl esterase (PME) (4) and their application during the pre-fermentative phase of vinification leads to an increase in the methanol content of the finished wine (5,6). ...
Article
Methanol is natural ingredient of alcoholic beverages and soft drinks; however, the products of its metabolic transformations (formaldehyde and formic acid) are toxic to humans. The aim of this research was to assess the application of different physico-chemical treatments of pomace in order to find the most efficient method for reducing the methanol during fermentation with the least effect on the sensory properties of the wine. The following procedures were studied: addition of tannins in pomace, addition of phenolic acids, addition of d-galacturonic and pectic acid, use of bentonite and zeolite, heat treatment of pomace, thermosonication and treatment of pomace with microwaves. Fruit wine used in this study was produced from plums (Prunus domestica L.). Applied treatments showed variable efficiency in reduction of methanol formation in plum wine. It may be noted that the procedures that involved some form of thermal treatment were characterized by a significant decrease in the production of methanol (up to 60–70%) but mostly tended to have a negative impact on the sensory properties of the produced wines. However, exposure of pomace to microwaves for a short time, owing to the contribution of mechanisms of non-thermal nature (kinetic and chemical), allowed for a significant reduction in methanol formation with a negligible impact on the sensory properties. The decrease in methanol formation during fermentation using tannins, pectic acid, bentonite and zeolite was poor, with only a reduction of up to 15%. Obtained results are significant to the fruit wine and spirit industry, considering the common problem related to an increased content of methanol in these beverages. Copyright © 2016 The Institute of Brewing & Distilling
... e extraction difficult. Gensi, Kyamuhangire, and Carasco (1994) accomplished extraction of banana juice from ripe peeled or unpeeled bananas by a traditional method of mashing with hands in plastic basins using Imperata cylindrica grass as a processing aid. This study was conducted to elucidate traditional methods to produce banana juice in Uganda. Byarugaba-Bazirake (2008) applied commercial enzymes (Rapidase CB, Rapidase TF, Rapidase X-press and OE-Lallzyme ) in the processing of banana juice for wine production. The objective was to vary enzyme concentration at different range and observe the parameters influencing wine processes. Dhamsaniya and Varshney (2013) developed a process to evaluate whey bever ...
Article
The objective of this work was to develop a process with optimum conditions for banana juice. The procedure involves hydrolyzing the banana pulp by commercial pectinase followed by cloth filtration. Response surface methodology with Doehlert design was utilised to optimize the process parameters. The temperature of incubation (30-60°C), time of reaction (20-120min) and concentration of pectinase (0.01-0.05% v/w) were the independent variables and viscosity, clarity, alcohol insoluble solids (AIS), total polyphenol and protein concentration were the responses. Total soluble sugar, pH, conductivity, calcium, sodium and potassium concentration in the juice were also evaluated. The results showed reduction of AIS and viscosity with reaction time and pectinase concentration and reduction of polyphenol and protein concentration with temperature. Using numerical optimization, the optimum conditions for the enzymatic extraction of banana juice were estimated. Depectinization kinetics was also studied at optimum temperature and variation of kinetic constants with enzyme dose was evaluated.
... The extraction of that juice from banana and fermentation to produce banana wine using traditional methods is an important post-harvest activity in the family banana farming in eastern Africa. The production and sale traditional banana wine has greater importance to local population because it generates incomes to the family household [1]. The most popular drinks are banana wine and liquors. ...
Article
This research has the objective of analyzing and compare the microbial content of TBW manufactured in rural areas. To achieve our objectives, 3 samples from Ngoma and 3 from Musanze sectors have been collected and analyzed using Nutrient broth, Sabouraud, and Eosin methylene blue agar media. The results have shown that TBW made from Musanze and Ngoma contains many microbes from different species E Coli, Streptococcus, Staphylococcus, Lactobacillus, Enterobacter, Clostridium, and Bacillus have been identified. The results showed that the TBW lacks hygienic conditions which were worse in TBW prepared by feet in Ngoma. The TBW made in Ngoma contained more fecal coliforms 330/ml, total germs 302.3x10 7 /ml, yeasts, and molds 784x10 6 /ml compared to TBW made from Musanze containing 50/ml fecal coliforms 325/ml yeasts and molds and 523x10 6 /ml total germs. The total coliforms were the only category of microorganisms to be more numerous in Musanze TBW 117x10 4 /ml compared to 140x10 3 /ml of Ngoma. TBW from Musanze had high pH and alcoholic degree compared to Ngoma. TBW made from Ngoma had a shorter shelf life and bad smelling. Both Tbw did not respect the norms fixed by RBS, so the producers must improve the hygienic conditions and respect the norms of RBS.
... Besides mixed municipal solid waste, homogeneous organic solid waste is generated by agricultural and industrial activities in LMIC during agricultural harvests and agro-industrial processes comprising stems, stalks, peel, seeds and pulp (Krishna and Chandrasekaran, 1996). For instance banana, belonging to the family Musaceae and genus Musa, is a crop grown in 120 countries throughout the world (Byarugaba-Bazirake, 2008). Tanzania contribute large quantities of bananas grown in Africa while generating around 60 tonnes ha À1 of banana-related organic solid waste per harvest (Tock et al., 2010;Emmanuel et al., 2014). ...
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Use of black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae (BSFL) is among the solutions being explored to shift the value chain in organic waste management by producing valuable products. Although BSFL consume a range of substrates, nutrient-imbalanced materials with high hemicellulose and lignin content, e.g. manure and banana peel, yield low conversion into larval biomass. This study explored pre-treatment methods to improve the nutrient composition and digestibility of banana peel to achieve higher substrate conversion into BSFL biomass. The pre-treatment methods evaluated were microbial, chemical (non-protein nitrogen), heat-based, and combinations of these. All pre-treatments tested except heating resulted in more efficient BSFL conversion in terms of final larvae weight. The low BSFL responses in pre-treatments were caused by the observed high amounts of tannins and phenolic compounds mainly from the heating pre-treatment. Waste to biomass conversion ratio correlated negatively with substrate volatile solids (VS) and positively with the decrease in VS in pre-treatment. Microbial - 14 days pre-treatments provided the optimum pre-treatment time for the microorganisms to achieve maximum degradation of the substrates, facilitating larval assimilation of the released nutrients. Rhizopus oligosporus-14 days and ammonia + Rhizopus resulted in the most efficient BSFL treatment, measured as protein produced per kg incoming material.
... The activity of pectolytic enzymes during fruit processing for wine production is associated with the hydrolysis of pectic substances (which leads to the liquefaction of the pomace, yield increase, clarification and filtration) and the increased efficiency of colour and flavour component extraction (Byarugaba-Bazirake, 2008;Bayindirli, 2010). Commercial preparations of pectolytic enzymes are a mixture of polygalacturonase, pectin lyase, and pectin methyl esterase (PME) (Dietrich et al., 1991). ...
... However, anecdotal evidence suggests that some commercial TRWY intermittently produce undesirable high levels of volatile acidity (VA), which imparts vinegar-like nuances to the wines (Du Toit and Pretorius, 2000;Ugliano et al., 2007;Vilela-Moura et al., 2011). Acetic acid is the main contributor to VA in wine with odour detection levels ranging between 0.7 and 1.1 g/L (Byarugaba-Bazirake, 2008;Vilela-Moura et al., 2010). Even though, excessive levels of VA are mainly caused by lactic acid bacteria, acetic acid bacteria and wild yeasts, wine yeasts also contribute to VA, by producing acetic acid during alcoholic fermentation (Cordente et al., 2013;Luo et al., 2013). ...
Article
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A single Saccharomyces cerevisiae wine yeast strain produces a range of aroma and flavour metabolites (e.g. volatile thiols), as well as unfavourable metabolites (e.g. volatile acidity [VA]), during the alcoholic fermentation of white wine, especially Sauvignon blanc. The former contribute to the organoleptic quality of the final wine. Previous research showed that yeast-derived enzymes (proteins) are involved in the release of wine quality-enhancing or quality-reducing metabolites during fermentation. Small-scale winemaking trials were initiated to evaluate the protein expression and metabolite release of S. cerevisiae hybrid yeasts producing tropical fruit aroma. Commercial ‘thiol-releasing’ wine yeasts (TRWY) were included in winemaking trials as references. Improved hybrids were identified that showed enhanced thiolreleasing abilities, specifically 3-mercaptohexanol (3MH), and lower VA formation during the production of Sauvignon blanc wines compared to some commercial TRWY references. It is noteworthy that the hybrid NH 56 produced wines with the second highest 3MH levels after hybrid NH 84, and with the lowest acetic acid of all strains included in this study. This yeast was also the only strain to have downregulated proteins linked to amino acid biosynthesis, the pentose phosphate pathway, glycolysis, and fructose and galactose metabolism during the lag phase. Furthermore, differences in protein expression were reflected in the variation in metabolite release by different strains, thereby confirming that enzymes (proteins) are the final effectors of metabolite release.
... As indicated in Figure 2 (d), both B and GA wines showed the highest turbidity compared to other samples. The turbidity of I and G wines was within the range reported by Byarugaba-Bazirake [21]. The higher turbidity of wine might be due to poor processing of banana juice prior to fermentation and/or poor filtration of the final product which is assigned mainly to the polysaccharides, pectin and starch [22]. ...
Article
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This study aimed to evaluate the physicochemical and bacteriological characteristics of different types of banana wine (Urwagwa) produced in Southern province of Rwanda. Both conventional (not bottled i.e from Bulinga (B) and Gahogo (GA)) and modern produced banana (bottled i.e Igisubizo from Ruli (I) and Ganzinyota from Ruvumera (G)) wines were analyzed and compared. Results showed that the alcohol content (v/v) of I, G, B and GA was 25.9% , 26.1%, 12.0% and 40.
... Furthermore, the cost of the enzyme is relatively expensive to be applied in wine production (Donsì et al., 2010). The importance of enzyme purity and the difficulty of enzyme storage at suitable conditions inhibit the use of enzymatic processing (Byarugaba-Bazirake, 2008;Sacchi et al., 2005). ...
... However, anecdotal evidence suggests that some commercial TRWY intermittently produce undesirable high levels of volatile acidity (VA), which imparts vinegar-like nuances to the wines (Du Toit and Pretorius, 2000;Ugliano et al., 2007;Vilela-Moura et al., 2011). Acetic acid is the main contributor to VA in wine with odour detection levels ranging between 0.7 and 1.1 g/L (Byarugaba-Bazirake, 2008;Vilela-Moura et al., 2010). Even though, excessive levels of VA are mainly caused by lactic acid bacteria, acetic acid bacteria and wild yeasts, wine yeasts also contribute to VA, by producing acetic acid during alcoholic fermentation (Cordente et al., 2013;Luo et al., 2013). ...
Article
Full-text available
Wine yeasts (Saccharomyces cerevisiae) vary in their ability to develop the full aroma potential of Sauvignon blanc wine due to an inability to release volatile thiols. Subsequently, the use of 'thiol-releasing' wine yeasts (TRWY) has increased in popularity. However, anecdotal evidence suggests that some commercially available TRWY intermittently exhibit undesirable characteristics for example, volatile acidity (VA) formation. Therefore, a trial was undertaken to select and evaluate S. cerevisiae hybrids for the production of Sauvignon blanc wine with enhanced fruity and tropical aromas, but low VA. Hybrids were characterised by clamped homogeneous electrical field (CHEF) DNA karyotyping and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) biotyping, and subsequently trialled against top commercial TRWY that is, Zymaflore VL3 and Zymaflore X5 (Laffort Oenologie), and Fermicru 4F9 (DSM Oenology) in laboratory-scale Sauvignon blanc vinifications during 2013. Most hybrids produced wines with VA levels significantly lower than those produced with Zymaflore VL3, Zymaflore X5 and Fermicru 4F9. Low VA forming hybrids also produced wines with tropical wine aroma notes. Wines produced by Fermicru 4F9 had the lowest acetic acid (the main volatile acid) of the commercial TRWY in this study. However, some hybrid yeasts produced wines with less acetic acid on average than wines produced by Fermicru 4F9. Overall, hybrids NH 6, NH 48, NH 56, NH 88 and NH 145 produced wines with enhanced tropical fruity aroma, but lower VA compared to wines produced by commercial TRWY.
Conference Paper
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Đề tài “Sự biến đổi hóa lý của rượu vang chuối già (Musa acuminata colla cv.) trong quá trình bảo quản” xác định được tỷ lệ nấm men bổ sung 0,3% có thể rút ngắn thời gian lên men còn 8 ngày mà chất lượng sản phẩm tốt đạt yêu cầu. Bên cạnh đó, trong quá trình tồn trữ rượu vang chuối ở hai mức nhiệt độ phòng và nhiệt độ lạnh, không có sự khác biệt hàm lượng rượu trong khi hàm lượng methanol, acid acetic, ethyl acetate, độ trong tăng dần theo thời gian. Ngược lại có sự giảm đáng kể hàm lượng đường khử của rượu vang chuối sau 6 tháng bảo quản. Khi so sánh sự khác biệt giữa hai mức nhiệt độ phòng và nhiệt độ lạnh, chỉ có hàm lượng ethyl acetate và độ trong có sự khác biệt ý nghĩa ở mức 5%.
Chapter
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Chapter
The quality of bakery products could be improved by the use of a variety of additives, but the use of natural additives is gaining popularity. Value addition for raw commodities is the slogan of modern agriculture. Frozen dough products are one recent example of value-added cereal products. Water distribution changes that usually occur during extended frozen storage and freeze-thaw cycles contribute to the extended proofing time and reduced loaf volume of frozen bread dough, and thus result in stability problems in final products. Enzymes are also considered potential natural additives that have the ability to interact or modify the starches and gluten network in a dough system, and thus behave as dough improvers and strengtheners.
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This study aims to verify the nutritional potential of three enriched flours that could be used to fight child malnutrition. To do this, it relies on a traditional dish prepared from senescent plantain called dockounou. Indeed, dockounou is a ready-to-eat dish that is popular in Côte d'Ivoire, accessible to get, and beneficial to people of all socioeconomic backgrounds. It is, however, deficient in some macronutrients and difficult to conserve after cooking. The enrichment and conversion of this dish into available and accessible infant flours can allow many women with reduced financial conditions to have simple and effective food for their children from 6 to 59 months. Also, from senescente plantain, three types of dockounou incorporated with maize, soybeans and fish were made according to the optimized method of Kra et al. (2014). After drying in an oven, the dockounou were turned into flours, and their biochemical and functional properties were assessed. The results obtained showed that enriched dockounou flours had fat and protein contents ranging from 9.73 ± 0.11 % to 10.00 ± 00 % and from 11.30 ± 00 % to 14.13 ± 1.29 % respectively. The energy value of these flours varied from 375.06 ± 1.1 Kcal to 375.89 ± 0.51 Kcal. All these values are in line with FAO/WHO standards and are able to meet daily requirements of children under 10 years age. After statistical analyses, it emerged that Ms2 flour was the best maize enriched dockounou flours.
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Roselle petals can be made into extracts as a source of raw material for food products and other products. Previous research states that the use of pectinase and cellulase enzymes can increase the yield including the anthocyanin content. This study aims to optimize the extraction conditions of roselle flower petals (Hibiscus sabdariffa L.) using pectinase and cellulase enzymes by using Response Surface Methodology (RSM). The treatment conditions were using pectinase and cellulase enzyme (1: 1) with concentrations in the range between 500-1500 ppm, extraction temperature between 35-65 oC and extraction time between 30-90 minutes. Analysis of the best treatment was carried out on the yield level, anthocyanin content and total dissolved solids tested using central composite design, obtained R2 values for the three responses of 0.6. The results showed that based on the surface response, the optimum conditions of the best extraction of the rosella at the addition of enzyme concentration of 1000 ppm, extraction temperature of 50 oC and extraction time of 10 minutes. In this condition, the yield of dried extracts of rosella was 84,20%, anthocyanins content 479,70 mg/L and total soluble solid 2,13 oBrix.
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This research aimed to optimize the extracting condition of banana peel (BP) and to investigate the effect of organic banana peel extract (BPE) on the immunity of giant freshwater prawn (Macrobrachium rosenbergii). The result demonstrated that the optimum extracting condition of organic BPE was 50% v/v of methanol at 100°C for 10 min. Under this condition, the maximum total phenolic content and extraction yield of 10.44 mg of gallic acid equivalents (GAE) per g of dry matter (mg GAE/g DM) and 33% w/v were obtained respectively. The organic BPE could inhibit an aquatic pathogen Aeromonas hydrophila at the minimum inhibitory concentration of 625 µg/disc. The main phytochemicals in organic BPE showed two major biological functions, which are antioxidant and antipathogenic activities. Subsequently, the effects of organic BPE on the immunity of M. rosenbergii were investigated. The results demonstrated that the organic BPE could increase immunity and phagocytic activity and decrease the susceptibility of M. rosenbergii. Moreover, the organic BPE could also increase total as well as differential haematocyte count, decrease the coagulation time and increase the total protein in serum of M. rosenbergii. The phagocytic activity of prawn was enhanced to 82.00% by using an organic BPE at 6 µg/g. At the same time, the cumulative mortality was declined to lower 20% after 6 days of organic BPE injection. In conclusion, organic BPE can be a potential immunostimulant in giant freshwater prawn culture. The utilization of BP in aquaculture can further add the value of BP and reduce organic pollutants.
Article
Mycotoxins, together with endotoxins, represent important classes of naturally occurring contaminants in food products, posing significant health risks to consumers. The aim of this study is to investigate the occurrence of both Fusarium mycotoxins and endotoxins in commercially produced traditional banana beer. Two brands of commercially produced traditional banana beer were collected from a local retail market in Kigali, Rwanda. Beer samples were analysed for the presence of deoxynivalenol (DON), fumonisin B(1) and zearalenone (ZEA), using an enzyme-linked immuno-sorbent assay (ELISA) method. The quantification of bacterial endotoxin using Limulus amoeboecyte lysate (LAL) assay was also conducted. The contamination levels were 20 and 6.7 µg kg(-1) for DON; 34 and 31.3 µg kg(-1) for FB(1); 0.66 and 2.2 µg kg(-1) for ZEA in brands A and B of the beers, respectively. Results indicate that the levels of Fusarium toxins and bacterial endotoxin reported in this study did not pose adverse human health effects as a result of drinking/consuming banana beer. However, exposure to low/sub-threshold doses or non-toxic levels of endotoxins magnifies the toxic effect of xenobiotic agents (e.g. fungal toxins) on liver and other target organs. Considering Fusarium toxins and/or endotoxin contamination levels in other agricultural commodities intended for human consumption, health risks might be high and the condition is aggravated when beer is contaminated by mixtures of the mycotoxins, as indicated in this study.
Article
Full-text available
This review focuses on acetic acid bacteria in the winemaking process. The enumeration, isolation and identification of acetic acid bacteria from grapes and wines are discussed. This is followed by an outline of the conditions and measures that can assist the wine producer to inhibit the unwanted growth of acetic acid bacteria in wine, which include the ethanol concentration, low pH, minimum oxygen pick-up, temperature control, addi- tives as well as clarification and filtration. The metabolism of acetic acid bacteria, which include ethanol, carbohydrate, organic acid and glycerol metabolism, and which can form spoilage products, are also reviewed, as well as the interaction between acetic acid bacteria and other wine-related microorganisms.
Article
Winemaking as a form of food preseIVation is as old as civilization. Wine has been an integral component of people's daily diet since its discovery and has also played an important role in the development of society, reli­ gion, and culture. We are currently drinking the best wines ever produced. We are able to do this because of our increased understanding of grape growing, biochemistry and microbiology of fermentation, our use of ad­ vanced technology in production, and our ability to measure the various major and minor components that comprise this fascinating beverage. Historically, winemakers succeeded with slow but gradual improvements brought about by combinations of folklore, obseIVation, and luck. How­ ever, they also had monumental failures resulting in the necessity to dis­ pose of wine or convert it into distilled spirits or vinegar. It was assumed that even the most marginally drinkable wines could be marketed. This is not the case for modem producers. The costs of grapes, the technology used in production, oak barrels, corks, bottling equipment, etc. , have in­ creased dramatically and continue to rise. Consumers are now accustomed to supplies of inexpensive and high-quality varietals and blends; they con­ tinue to demand better. Modem winemakers now rely on basic science and xvi Preface xvii the systematic application of their art to produce products pleasing to the increasingly knowledgeable consumer base that enjoys wine as part of its civilized society.
Article
East African Highland bananas are unique to East Africa and are a staple food for more than seven million people in Uganda. Banana is usually eaten as a cooked green vegetable but a significant income for many farmers is derived from beverage products prepared from particular cultivars. The National Banana Programme in Uganda has been using surveys to identify researchable issues on areas of constraint for banana farmers. Postharvest handling, food and drink products from bananas and the use of banana 'wastes' are described in this paper.
Book
Section I-Sampling, Fermentation, and Production Analysis.- 1 / Fruit Quality and Soluble Solids.- 2 / Alcoholometry.- 3 / Extract.- 4 / Hydrogen Ion (pH) and Fixed Acids.- 5 / Volatile Acids.- 6 / Carbohydrates: Reducing Sugars.- 7 / Phenolic Compounds and Wine Color.- 8 / Oxygen, Carbon Dioxide, and Ascorbic Acid.- Section II-Microbial Stability.- 9 / Sulftir Dioxide.- 10 / Sulfur Containing Compounds.- 11 / Other Preservatives: Sorbic Acid, Benzoic Acid, and Dimethyldicarbonate.- 12 / Wine Microbiology.- Section III-Chemical Stability.- 13 / Tartaric Acid and its Salts.- 14 / Copper.- 15 / Iron and Phosphorus.- 16 / Nitrogenous Compounds.- Section IV-Remedial Actions.- 17 / Fining and Fining Agents.- 18 / Correction of Tartrate Instabilities.- 19 / Removal of Copper and Iron-The Hubach Analysis.- Appendixes.- Appendix I /Chromatographic Techniques.- Appendix II /Laboratory Reagent Preparation.- Appendix III /Laboratory Media and Stains.
Article
Fermentation studies investigated the effects of pectolase (P) percentages (0 ° , 0.15 ° , 0.5 ° , 1 ° ) at varying incubation periods (1 h, 4 h, 24 h) at 23 - 1 ° C on physicochemical, microbiological and sensory qualities of banana wines. Addition of enzyme had no effects ( p > 0.05) on percentage wine yield, degrees Brix, percentage alcohol, sulphur dioxide (SO 2 ), pH or titratable acidity except for ( p < 0.05) colour, volatile acidity and tannin content. Longer incubation period resulted in changes in all parameters ( p < 0.05) except degrees Brix, percentage alcohol and pH. Wines with 1% P (4 h) and 1% P (24 h) were judged as standard wines. Wine quality was stable for most parameters during storage at 22-25 ° C for 4 months with better clarity and lower SO 2 .
Article
Traditional banana ripening processes for juice extraction, using the rack and pit methods, were carried out on farm to assess and compare the conditions in the respective ripening chambers and the suitability of the resulting ripe bananas for juice extraction. During ripening, high temperatures (23-32°C) were attained and ethylene was produced. Ethylene reached peak concentrations of 250 and 500 mg kg−1 for the rack and the pit methods respectively. Owing to the continued respiration of the bananas, the oxygen concentration fell and carbon dioxide accumulated, however the bananas attained a bright yellow colour on ripening. There was a significant difference in environmental conditions between the rack and pit ripening chambers. This did not affect ripening and it was possible to extract juice from bananas ripened by either method. However, some juice extraction failures were encountered. These preliminary studies suggest that the success or failure of banana juice extraction depends partly on conditions of ripening, in particular temperature.© 1999 Society of Chemical Industry
Article
Protein−polyphenol hazes form in beer, wine, and fruit juices and can limit shelf life. Haze-active protein is higher in beer than the other beverages. Haze-active polyphenol is highest in apple juice and red wines, variable in grape juices, and low in beer and white wine. A systematic study of factors that influence haze formation was carried out in a model system. Pectin, arabinogalactan, and poly(galacturonic acid) led to increased haze while free amino acids and other carbohydrates had no effect. Maximum haze occurred near pH 4 with less haze at higher and lower pH's. As ethanol concentration increased near pH 4, the haze at first declined, but further increases in ethanol led to increased haze. It appears that haze formation is similar in all the beverages examined and may be explained by a single mechanism. This has implications for analysis of haze-active constituents and beverage stabilization. Keywords: Haze-active protein; haze-active polyphenol; pH; alcohol; turbidity; beer; wine; fruit juices
Article
A comparative study of the enzymatic and mechanical banana juice extraction methods and the respective juices produced was carried out using Kayinja bananas (ABB genotype) imported from Uganda. In the enzymatic extraction process, macerated ripe banana pulp was incubated with a commercial enzyme preparation (Pectinex Ultra SP-L) at 50 °C for 2 h. In the mechanical extraction process the ripe banana pulp was mixed with stretched strips of polythene and worked with a dough mixer at room temperature for 20 min (on average) until the juice appeared. Significantly (p < 0.05) higher ‘pure’ juice yield (604 g kg−1 pulp) was obtained with the enzymatic method than with the mechanical method (541 g kg−1 pulp). However, adding water to the spent pulp from the mechanical process and extracting dilute juice improved the juice yield to 757 g kg−1 pulp. The enzyme-extracted juice had significantly (p < 0.05) higher soluble solids, titratable acidity, fructose, glucose, total nitrogen, density and mineral potassium. However, the mechanically extracted juice had significantly higher sucrose, pH and viscosity. Although the mechanical extraction process suffers from occasional juice extraction failures, it offers an opportunity to extract banana juice without excessive energy expenditure, and the juice produced is wholesome with a superior flavour to that produced by the enzymatic method.© 2002 Society of Chemical Industry
Article
Twenty-four wines from four communes in Bordeaux were evaluated by descriptive analysis by trained assessors. The same 1976 wines were assigned quality ratings by Masters of Wine (MW). The major aroma difference between the wines was attributed to variation in the intensity of the ‘green bean/green olive’ character by canonical variates analysis (CVA) of the aroma descriptor ratings across wines. The CVA of the flavour by mouth ratings showed the wines to be discriminated primarily on the basis of astringency and bitterness. By multivariate analysis of variance across regions, and by examination of the configurations derived from the CVA across wines, it was shown that the wines did not vary significantly between communes. No significant difference between the wines in quality ratings of the MWs was found.
Article
Experiments were conducted to determine the effects of commercial enzyme preparations on viscosity reduction and filterability of banana juice, and the effectiveness of various anti-browning treatments on clarified juice. Two different combinations of pectinase, cellulase and hemicellulase were more effective in reducing viscosity and improving filterability of both green and ripe banana purees than a pectinase, galactomannanase or cellulase after incubation periods of 3, 6 and 9 h. An alpha-amylase was not effective in reducing viscosity as compared to the control, even of green banana puree high in starch. Potassium metabisulfite (100 mg/L) was more effective in producing a light colored juice with stable color than two heating methods (heating whole, unpeeled bananas at 100°C for 11 min.; heating puree at 80°C for 1–2 min) and ascorbic acid (470 mg/L). Polyphenoloxidase was active in the clarified juices treated with ascorbic acid and the control, and both darkened over time. Sensory analysis indicated that all the juices had similar banana flavor intensity.
Article
Pectinolytic enzyme treatments to increase the yield, reduce the viscosity and clarify the juice obtained from ripe banana pulp were studied. Six commercial enzyme preparations were tested on pulps of different ripenesses. Optimal conditions with respect to enzyme concentration, incubation temperature, time and pH levels are reported for the two most effective enzyme preparations. Clear juice yields of between 55 and 60% (based on pulp weight used) are obtained from pulp incubated at 45°C for 1 hr with 0.01% w/w of enzyme by subsequent centrifugation at 2900 maximal relative centrifugal force for 20 min. This corresponds to a yield of total and reducing sugars present in the pulp of over 75%. Untreated control pulps yield less than 5% of juice under these conditions. Hydraulic pressing of the pulps at 16 kg/cm2 gives similar juice yields to those obtained by centrifugation. The juice has an excellent flavour and aroma and provides a possible use for the large quantities of reject bananas available in producer countries.
Article
The amount of haze-active protein in apple juice was determined by adding tannic acid to induce haze followed by turbidimetry. Turbidity was essentially linear with protein concentration. PVPP treatment prior to tannic acid addition appeared to remove endogenous polyphenols and resulted in slightly weaker response. Adding gelatin to apple juices or clarified ciders induced hazes in response to content of haze-active polyphenols. At an appropriate gelatin concentration turbidity was nearly linear with polyphenol concentration. Treatment with bentonite prior to gelatin addition appeared to remove endogenous protein. Temperature control during the induction period was critical to reproducibility.
Article
Incluye bibliografía e índice
Article
Yeasts are predominant in the ancient and complex process of winemaking. In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts, with the final stages invariably being dominated by the alcohol-tolerant strains of Saccharomyces cerevisiae. This species is universally known as the 'wine yeast' and is widely preferred for initiating wine fermentations. The primary role of wine yeast is to catalyze the rapid, complete and efficient conversion of grape sugars to ethanol, carbon dioxide and other minor, but important, metabolites without the development of off-flavours. However, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing quest for specialized wine yeast strains possessing a wide range of optimized, improved or novel oenological properties. This review highlights the wealth of untapped indigenous yeasts with oenological potential, the complexity of wine yeasts' genetic features and the genetic techniques often used in strain development. The current status of genetically improved wine yeasts and potential targets for further strain development are outlined. In light of the limited knowledge of industrial wine yeasts' complex genomes and the daunting challenges to comply with strict statutory regulations and consumer demands regarding the future use of genetically modified strains, this review cautions against unrealistic expectations over the short term. However, the staggering potential advantages of improved wine yeasts to both the winemaker and consumer in the third millennium are pointed out.
Article
The aim of this work was the construction of an oenological Saccharomyces cerevisiae strain able to overexpress the PGU1 gene in order to be used in trial fermentations. The recombinant strain is able to secrete an active endopolygalacturonase into the medium leaving its fermentation ability essentially unchanged. Wines obtained with the recombinant strain and the untransformed counterpart did not differ in their physicochemical parameters or major sensory characteristics. The time needed for wine filtration was dramatically reduced in wines elaborated with the PGU1 recombinant strain, and was comparable to the filtration time shown by wines elaborated from must supplemented with fungal pectolytic enzymes. The oenological strain constructed in this work secretes an endopolygalacturonase into the wine in an efficient manner, resulting in an improvement in wine filtration but preserving wine typicality and keeping the methanol levels unchanged. The PGU1 recombinant strains could be used in oenological fermentations as an alternative to commercial pectolytic enzymes of fungal origin.
Article
Wine producers are facing intensifying competition brought about by a widening gap between wine production and wine consumption, a shift of consumer preferences away from basic commodity wine to top quality wine, and economic globalization. Consequently, they are calling for a total revolution in the 'magical' world of wine. The process of transforming the wine industry from a production- to a market-orientated industry results in an increasing dependence on, amongst others, biotechnological innovation. Market-orientated wine-yeast strains are currently being developed for the cost-competitive production of wine with minimized resource inputs, improved quality and low environmental impact. The emphasis is on the development of Saccharomyces cerevisiae strains with improved fermentation, processing and biopreservation abilities, and capacities for an increase in the wholesomeness and sensory quality of wine.
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