Recycling preservation solutions in black ripe olive processing

The purpose of this study was to evaluate the reuse of the liquid employed to preserve black ripe olives in a new fermentation process. The fermentation of olives in these reused solutions (ozonated, acetic acid distillate and old storage solutions) produced similar results as with a fresh acetic acid solution. The pH was between 3.8 and 4.1, and the free acidity ranged from 1.4 to 2.6. Yeasts and acetic acid bacteria were the predominant microorganisms, while lactic acid bacteria grew occasionally after 6–8 months of storage. Off‐odours, fruit defects or any other spoilage were not detected in any case. Moreover, the quality of the darkened product (colour, firmness, flavour) was statistically similar for all treatments, although fruits preserved in a reused ozonated liquid showed less dark fruits (R₇₀₀ = 9.7–10.7) than the others (R₇₀₀ = 7.7–9.3). These results open the possibility of reusing the black olive solutions in a new preservation process.     

Sterols,fatty alcohol and triterpenic alcohol changes during ripe table olive processing

The aim of the work was to study the effects of processing on the unsaponifiable matter, sterols and fatty and triterpenic alcohol in ripe olive fat (Manzanilla and Hojiblanca cultivars) and to disclose the most influential factors using GLM, PCA and DA. There were significant effects of cultivars or ps on unsaponifiable matter, β-sitosterol, Δ⁵-avenasterol, total sterols, 1-docosanol, 1-tetracosanol (ps), erythrodiol and percentage erythrodiol + uvaol. The values of most of these parameters were within the limits established by the EU Directives for olive and pomace oils but classification of the respective oils was not conclusive. Predictive discriminant analysis using these variables permitted 100% success in the classification according to cultivars and ps (68% in the case of cross validation). Results revealed that some influential steps should be re-designed, particularly the storage phase, in order to minimise changes in the studied fat components during ripe olive processing.     

Use of manganese in ripe olive processing

 The use of manganese (Mn) salts in various steps of the processing of ripe olives of the Manzanilla cultivar can increase their oxidation rate and produce darker olives. The best results were obtained by adding a Mn concentration of 40 mg/l to the storage brine and allowing a period of contact of at least 15 days. Good results were also obtained when using a Mn concentration of 100–250 mg/l in a “desalting” step before darkening, as well as variable periods of contact and temperatures. When Mn was added to the washing waters after any of the lye treatments of the darkening step, especially the first one, the effect was also appreciable, although varying degrees of Mn residues in the flesh were found. Addition of Mn to the storage brine and application of the usual darkening process produced more uniform and darker ripe olives with Mn residue levels at below 30 mg/kg, which is approximately 15% of the recommended daily intake for this metal. Results suggest that this cation, recognized as GRAS in the USA, may be used as a catalyst in the darkening of ripe olives if authorized as a processing aid. Received: 25 July 1997 / Revised version: 16 October 1997     

Use of manganese in ripe olive processing

 The use of manganese (Mn) salts in various steps of the processing of ripe olives of the Manzanilla cultivar can increase their oxidation rate and produce darker olives. The best results were obtained by adding a Mn concentration of 40 mg/l to the storage brine and allowing a period of contact of at least 15 days. Good results were also obtained when using a Mn concentration of 100–250 mg/l in a “desalting” step before darkening, as well as variable periods of contact and temperatures. When Mn was added to the washing waters after any of the lye treatments of the darkening step, especially the first one, the effect was also appreciable, although varying degrees of Mn residues in the flesh were found. Addition of Mn to the storage brine and application of the usual darkening process produced more uniform and darker ripe olives with Mn residue levels at below 30 mg/kg, which is approximately 15% of the recommended daily intake for this metal. Results suggest that this cation, recognized as GRAS in the USA, may be used as a catalyst in the darkening of ripe olives if authorized as a processing aid. Received: 25 July 1997 / Revised version: 16 October 1997     

Biochemical changes during processing of traditional Jinhua ham

Jinhua ham is the most famous traditional meat product of China and one of the most famed dry-cured hams in the world. Its processing consists of six stages: green ham preparation, salting, washing and sun-drying and shaping, ripening, and post-ripening. Intense proteolysis and lipolysis occur during processing period. As a result, the content of free amino acids in final ham products is 14-16 times that of green ham, and 191 volatile compounds have been identified during processing, which make a major contribution to the flavor of Jinhua ham.     

Catalytic effect of metal cations on the darkening reaction in ripe olive processing

The darkening step in ripe olive processing can be accelerated by using different metal cations, particularly cobalt, manganese and iron, in the aeration liquid. It was found that manganese and iron ions increased the rate of the darkening reaction as their content in the liquid increased from zero to 9 mM. Manganese cations only had a catalytic effect on the darkening reaction, while iron ions also fixed the dark colour formed when olives were bottled and sterilized. However, the rate of oxidation of the orthodiphenols in the olive flesh (hydroxytyrosol and caffeic acid) was slightly modified when manganese or iron was added to the aeration liquid. The better dark surface colour obtained when manganese or iron ions were added to the aeration liquid remained after bottling and sterilization of olives in a ferrous gluconate solution. These results suggest that manganese could be used to catalyse the darkening reaction since this cation is generally recognized as safe.     

Aerobic treatment of black ripe olive processing streams to reduce biological contamination

A new aeration treatment of black ripe olive streams prior to their vacuum evaporation was studied. It was found that the aeration for two days of these solutions reduced the chemical oxygen demand (COD) of the distillate phase (>80%) generated during their vacuum evaporation; although the temperature (14–38 °C) and the air flow rate (10–50 L air/h/L) had a great influence on this reduction. Moreover, the COD in the distillate was mainly associated with the presence of acetic acid (~400 mg/L) and ethanol (~500 mg/L), the later substance being eliminated by strong aeration. Additionally, the growth of native aerobic microorganisms, mainly Acetobacter, increased the pH of the wastewater to 7–8 units, thus avoiding evaporation of the acetic acid salt formed. These results make the use of the distillate for plant irrigation viable and its discharge into municipal depuration plants possible, given the low COD (<500 mg/L) reached with this new method.Industrial relevanceThe worldwide production of table olives is annually increasing but the management of the solutions generated during olive processing is limiting this expansion, in particular due to their high salt content. Factories are nowadays concentrating these solutions by using vacuum evaporation but the contamination of the distillate is too high. The present work has been carried out based on industry demand for low cost and easy handle technology able to reduce COD in distillates. The results of the present study showed that the content in ethanol and acetic acid of distillates can be reduced to a large extend by simple aerating of the solutions prior to the vacuum evaporation step, and this open the possibility of their reuse for plant irrigation.     

Influence of olive tree irrigation and the preservation system on the fruit characteristics of Hojiblanca black ripe olives

In this study, the effect of olive tree irrigation, the use of salt in preservation liquids and the reuse of sodium hydroxide solutions (lye) on the weight, shriveling, firmness and phenolic content of Hojiblanca processed olives was investigated. A weight loss in fruits of up to 5% during the preservation stage was observed, particularly for olives from irrigated trees and stored in brines. By contrast, a weight gain of up to 7% was achieved during the darkening stage, whose intensity was increased by using fruits from non-irrigated trees and preserved in a salt-free environment as well as fresh lye for the debittering step. Moreover, shriveling particularly appeared in fruits from non-irrigated olive trees, this defect being more intense if lye was reused. Firmness was also affected by the studied variables, and natural rainfed irrigation and the reuse of lye and salt in the preservation solutions gave rise to firmer olives. The content in phenolic compounds of black processed olives was higher in fruits from non-irrigated than irrigated trees, in particular those of hydroxytyrosol, tyrosol and luteolin 7-glucoside. Overall, these results will contribute to the knowledge of table olives processing and the industrial optimization of this sector.     

Lipolytic activity of the yeast species associated with the fermentation/storage phase of ripe olive processing

Ripe olives account for ca. 30% of the world's table olive production. Fruits intended for this type of product are preserved in an aqueous solution (acidic water or brine) for several months, where they may undergo a spontaneous fermentation. Enterobacteriaceae and lactic acid bacteria were not detected in the present survey during storage. Thus, the work focused on studying the yeast microflora associated with the ripe olive storage of Manzanilla and Hojiblanca cultivars in acidified brines. A total of 90 yeast isolates were identified by means of molecular methods using RFLP analysis of the 5.8S-ITS rDNA region and sequencing of the D1/D2 domains of the 26S rDNA gene. The two most important species identified in both cultivars were Saccharomyces cerevisiae and Pichia galeiformis, which were present throughout the storage period, while Candida boidinii was detected during the later stages of the process. The species Pichia membranifaciens was detected only in the early stages of the Hojiblanca cultivar. The lipase assays performed with both extracellular and whole cell fractions of the yeast isolates showed that neither of the S. cerevisiae and P. galeiformis species had lipase activity, while the P. membranifaciens isolates showed a weak activity. On the contrary, all C. boidinii isolates gave a strong lipase activity. Change in olive fat acidity was markedly higher in the presence of the yeast population than in sterile storage, indicating that lipases produced by these microorganisms modify the characteristics of the fat in the fruit.     

Colour and texture changes during sterilization of packed ripe olives

There were no temperature- or time-dependent significant changes in colour or iron content of two cultivars of bottled ripe olives during heat sterilization at temperatures between 117 and 129°C. the addition of calcium had no effect on the activation parameters of texture, although the olives were always firmer when the cation was added. the z-values for the texture of ripe olives were found to be around 20°C and the average activation energy was 138 kJ/mol.     

Industrial implementation of black ripe olive storage under acid conditions

Restrictions on the discharge of chloride in wastewater streams have recently increased, and processors of black ripe olives have to look for alternative storage systems to the traditional brines. Ripe olives of the Hojiblanca variety were stored under aerobic and anaerobic conditions in industrial underground tanks for one year. The aerobic systems assayed with or without NaCl produced a continuous consumption of sugars as they diffused from the fruits to the surrounding liquid. At the same time sugars accumulated in the liquid for months when anaerobic conditions were employed and a high concentration of acetic acid was used. In the end, glucose was consumed with time as well and, in addition to yeasts, acetic acid and lactic acid bacteria grew in the cover solutions. The assessment of olives stored under the different systems and processed as black ripe olives revealed that the traditional aerobic brines gave rise to darker and firmer fruits. However, olive industries must eliminate chlorides from their waste streams. Promising new storage systems were (i) anaerobic preservation of olives in water with an initially high concentration of acetic acid, and (ii) aerobic preservation in water with an initially low concentration of acetic acid. Both systems produced a good quality product, free of microbial spoilage and organoleptic defects.     

Biochemical changes occurring during the manufacture of budu

The changes that occur during the commercial production of budu, a Malaysian fish sauce were examined. It was shown that the maximum volume of liquid was produced after 140 days and that proteolysis continued to occur until 200 days when 56% of the insoluble fish protein had been hydrolysed into soluble form. The colour was produced early during the fermentation. The aroma constituents, ammonia and trimethylamine, were produced early in the fermentation process, but the volatile fatty acids did not appear when fresh fish (Stolephorus) was used for the fermentation. In the commercial production, n-butanoic acid concentration remained constant during the fermentation but ethanoic acid did increase during the period. The salt concentration and the pH were approximately constant throughout, at 26% and 5.65, respectively.     

鱿鱼加工废弃物自溶水解过程中的生化变化

研究鱿鱼加工废弃物自溶水解过程中的生化变化规律,为鱿鱼加工废弃物的利用提供指导。利用鱿鱼加工废弃物所含的内源蛋白酶对原料蛋白质进行水解,选择原料的氨基酸组成和水解液的α-氨基态氮、总酸、可溶性总氮、TVB-N、pH、水解度及游离氨基酸为生化研究指标,得到其在自溶水解过程中的变化规律。结果表明原料的总氨基酸含量为10.7146g/100g,经过48h的自溶水解,部分蛋白质被内源蛋白酶转化成氨基酸等成分,水解度达到(26.20±0.64)%;TVB-N含量为(63.68±2.39)mg/100g。证明鱿鱼加工废弃物是一种营养丰富的蛋白质资源,所含的内源蛋白酶可以在鱿鱼加工废弃物深加工过程中较好地被利用。     

发酵香肠成熟过程中的生化变化

本文综合概述了有关发酵香肠在成熟过程中的一系列复杂生物化学变化及其影响因素,并提出今后有关发酵香肠的主要研究方向.     

鱿鱼副产物自溶水解过程的生化变化及其机理

系统地研究了鱿鱼加工副产物内源性蛋白酶自溶水解过程中氨基氮、总可溶性氮（TSN）、TCA可溶性氮（TCA-N）、挥发性盐基氮（TVB-N）、pH、总酸、水解度（DH）以及游离脂肪酸的变化。确定最佳自溶水解条件为:料水比1:1、温度45℃、原始pH、水解时间39h。自溶水解39h离心后上清液中的氨基氮、TSN、TCA-N的含量分别为0·626±0·025、1·234±0·049、0·589±0·018g/100mL,TVB-N含量为59·10±1·28mg/100mL,蛋白质水解度达到23·89%±0·13%。鱿鱼加工副产物内源性蛋白酶可以较好地水解其自身蛋白质,在39h的自溶水解过程中没有腐败现象发生。      

鲭鱼加工废弃物分段发酵过程中生化指标的动态变化

研究2次接种分段发酵过程中鲭鱼加工废弃物生化指标的动态变化情况。第1发酵阶段时添加葡萄糖并接种植物乳杆菌于30℃下厌氧发酵6 h,第2发酵阶段时接种产朊假丝酵母,并分别于25、30和35℃下好氧发酵42 h。结果表明:植物乳杆菌生物量有所提高,从初始7.83lg(CFU/g)分别上升至8.98、9.11和8.77 lg(CFU/g),而产朊假丝酵母生物量从初始5.62 lg(CFU/g)分别上升至6.52、6.64 lg(CFU/g)和下降至5.30 log(CFU/g),氨基态氮含量由初始0.28 g/100 g分别提高至0.31、0.43和0.36 g/100 g;TVB-N含量比初始62.26mg/100 g有所降低,分别为48.59、53.97和55.69 mg/100 g。发酵过程中水溶性蛋白质含量逐渐下降,非蛋白氮含量逐渐上升,p H变化与挥发性盐基氮呈正相关,总酸含量变化与p H呈负相关。     

Transformation of oleuropein and its hydrolysis products during Spanish-style green olive processing

Products obtained from elenolic acid glucoside hydrolysis during the storage of Spanish-style green olive brines were elenolic acid and glucose. The disappearance of elenolic acid glucoside from brines followed a first-order kinetics rate and was influenced by the storage temperature. Hydrolysis of this glucoside also occurred in brines ultrafiltered at 10000 Da pore size, indicating that no enzymatic action was needed to break the glycoside bond. Inoculation experiments with microorganisms obtained from a Spanish-style green olive brine demonstrated that this microflora was able to use the glucose formed from elenolic acid glucoside hydrolysis, although in our experiments only yeasts could grow in the assayed brines. It needs to be stressed that the glucose liberated by elenolic acid glucoside hydrolysis may represent about 20% of the total initial glucose in brines at the start of the fermentation step in Spanish-style green olive processing. © 1998 SCI.     

抗氧化剂对控制草莓打浆工序中Vc损失的效应

主要研究了草莓打浆工序中还原型VC含量的变化及其控制。结果表明,草莓打浆工序中VC损失严重,打浆中添加0.12%的六偏磷酸钠、0.03%的TBHQ可以提高还原型VC的保存率,添加0.03%的茶多酚可以提高还原型VC和氧化型VC的保存率,EDTA二钠和植酸对控制草莓打浆过程中VC损失的效果不明显。